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EXPERIMENTAL INQUIRIES 


RESPECTING 



WITH SOME 


PRACTICAL APPLICATIONS: 


BY WALTER R. JOHNSON, 

’ n j * r 

PROFESSOR OF MECHANICS AND NATURA.Ii PHILOSOPHY IN 

t 

THE FRANKLIN INSTITUTE, 


PHILADELPHIA. 


<£?<£> 








From the American Journal of Science and Arts , Vols. XIX <$• XX. 



EXPERIMENTAL INQUIRIES, &c. 


To account for the sudden explosions which sometimes occur in 
steam boilers, one hypothesis assumes that the metal, by undue ex¬ 
posure to the fire, and by a deficiency in the supply of water, be¬ 
comes intensely heated, and thereby affords a source of heat ready to 
act with great rapidity on any new portion of water which may be 
injected, or otherwise brought into contact with the heated surface. 
Whether the water be thrown up by ebullition, or caused to flow over 
the hot part of the boiler, by some change in the position of the lat¬ 
ter, will be of little consequence to the result, so long as we are sure 
of the presence of the dangerous generator. 

The construction of many steam boats, or rather the arrangement 
of their boilers, favors the presumption that a mere change of posi¬ 
tion has sometimes caused an explosion of the nature now alluded to. 

In the boats which navigate our western waters, eight or nine boil¬ 
ers of a cylindrical form, thirty inches in diameter, and about four¬ 
teen feet long, are laid side by side, lengthwise of the boat, so that 
allowing for interstices, from twenty two to thirty feet of the breadth 
of the deck, are taken up by the aggregate diameters of the row of 
boilers. They are almost uniformly constructed with returning flues 
from nine to twelve inches in diameter. 

The flue being placed eccentric, with respect to the main cylinder 
of the boiler, and indeed wholly below its centre, will be entirely 
immersed when the boiler is half filled with water. The furnace be¬ 
ing at one end, the flame passes along the whole length of the boiler 




4 Experimental Inquiries respecting Heat and Hapor. 

on the outside, and then entering the flue returns to a chimney 
near the upper or fire end. The boilers are all connected together 
by a pipe forming a water communication at bottom, and by anoth¬ 
er, forming a common steam passage above their upper surfaces. 
The lower guage cock is placed from one to three inches above the 
top of the flue; and so long as the deck remains perfectly horizon¬ 
tal, and the forcing pump for injecting water performs its office, a 
moderate degree of care, on the part of firemen and engineers, may 
insure the complete immersion of the flue. But when, from any 
cause, the boat inclines to either side, there will be a transfer of wa¬ 
ter through the lower connecting pipe, from the boilers on the eleva¬ 
ted, to those on the depressed side of the deck. A large number 
of passengers collecting on one side would doubtless be sufficient to 
cause a “ heeling” of a foot or more, and this would lay bare the 
whole of the flue in the upper boiler, and expose more or less sur¬ 
face of iron in every flue and boiler on the elevated side. Every 
pound of water thus transferred, serves to increase by double its own 
weight, the tendency of the boat to careen , and even after the other 
causes of unequal depression have ceased to act, the water thus dis¬ 
placed will continue its influence, and will not until after sometime, 
return to its former level through the pipe of communication. The 
removal of water from the part of the usual generating surface of 
metal, will cause the supply of steam to be diminished, so that the 
engine may appear to labor, even while the boiler is becoming red 
hot. This circumstance is known to have preceded some of the 
most frightful explosions, and it is but the natural result of employ¬ 
ing that caloric which ought to be producing steam, in merely rais¬ 
ing the temperature of metal, with the incidental effect of heating 
the steam already generated, considerably above the temperature 
which belongs to its actual density. Not only must those parts of the 
boilers and flues which are immediately exposed to the fire, become 
unduly heated, but, owing to the high conducting power of the me¬ 
tal, the upper arch of the cylinder, as well as the lower, will rapidly 
acquire the temperature due to the source of heat. Some may pos¬ 
sibly imagine that since the engine moves slowly for a time in conse¬ 
quence of a deficiency of generating surface, it will only move with 
the more speed when the accumulated force comes to be added to 
the regular supply. This might be the case if the excess were fur¬ 
nished with no greater rapidity than the deficiency had occurred. 
But whether we suppose the hot steam, or the hot metal to furnish 


5 


Experimental Inquiries respecting Heat and Vapor. 

heat of elasticity to the water which flows into the overheated boil¬ 
ers, the supply will be obtained almost instantaneously ;—a few se¬ 
conds, at most, being required to complete the operation of genera¬ 
ting, from water of a boiling temperature, all the steam which the iron 
of the boiler, even when red hot, is capable of producing. In order 
to determine with some precision, what effect will actually be pro¬ 
duced by the metal in such cases, I have performed a series of ex¬ 
periments tending to show the relation between the quantity of steam 
generated, the weight of the metal, the surface exposed, the time of 
action and the period of greatest effect. The trials have not been 
confined to rolled iron alone, but as the results must obviously be ef¬ 
fected by the specific caloric of the metal, I have extended them al¬ 
so to wrought iron in masses, to cast iron, copper, brass, silver and 
gold. 

These experiments were in part performed during the months of 
July and August last, when the temperature of the room seldom fell 
below 80°. This circumstance may, in addition to the other pre¬ 
cautions to avoid error in the results, assure us that the change of 
temperature in the water, between two consecutive experiments, can¬ 
not at any time have been sufficient to affect the quantity of vapor 
generated, or the time employed in its production. In order to exhi¬ 
bit an approximation to the actual state of the boiler, when in a con¬ 
dition to receive hot water on intensely heated metal, and when, of 
course, the whole excess of caloric would be employed in giving 
tbe elastic form, and none in raising temperature, I procured a cy¬ 
lindrical vessel of tinned iron 19J inches deep, 7 T \ inches in diame¬ 
ter, and capable of containing 28 r 5 ¥ lbs. of water at 60°. This was 
furnished with a cover of the same material, and with a wire handle 
like that of a bucket, for the convenience of suspending it to the 
beam of a pair of scales. The sides and bottom were covered ex¬ 
ternally with four successive folds of stout green baize, between each 
two of which was a batting of raw cotton, forming all together a 
coat of an inch thick. The non-conducting character of this de¬ 
fence may be inferred from the fact that fourteen pounds of water, 
left in tbe vessel for fourteen hours, was cooled only from 212°, to 
115°, or about 7° per hour, while the temperature of the apartment 
was 80° ; and that in the following twenty five hours, the same 
portion of water lost only 31°, being found at 84°, though the tem¬ 
perature of the air had in the mean time fallen to 76°. On another 
occasion, the loss was 9° per hour, or from 212° to 104° in twelve 
hours, in an apartment where the air was at G0°. 


6 Experimental Inquiries respecting Heat and Vapor. 

The vessel above described charged with about 15 lbs. of water, 
was suspended to one hook of the scale beam, while to the opposite 
was attached the usual pan for weights. The water was then brought 
to a state of rapid ebullition by heaters, previously plunged for an in¬ 
stant into another vessel of water, to take off any portion of ashes or 
oxide which might accidentally adhere to the surface. When assured 
that the water and its container had acquired the boiling temperature, 
I replaced the cover, and immediately adjusted the weights to an ex¬ 
act counterpoise. The piece of hot metal whose power of produ¬ 
cing steam was to be ascertained, was upon removing the cover im¬ 
mediately plunged into the boiling water, and permitted to remain 
until ebullition ceased. At that instant, the metal was withdrawn, the 
time noted, the lid adjusted and weight added on the side of the boil¬ 
er, to compensate for the evaporation of water, until the equilibrium 
was restored. The experiments were conducted with all due cau¬ 
tion to avoid the waste of water, which might ensue from the violent 
agitation, caused by plunging the metal all at once below the surface. 
The metal was either lowered gradually into the water, or, when plun¬ 
ged in immediately, was suspended to a wire, attached above to a 
cover, perforated with numerous holes, to allow the escape of steam, 
and furnished with a broad funnel shaped rim to receive and return 
any water which might be projected through the apertures. 

In order to avoid communicating to the apparatus a temperature 
above that of the liquid, the metal was suspended in the water, and 
not allowed to touch the sides or bottom of the cylinder. 

The difficulty of ascertaining with precision the temperatures 
above the boiling point of mercury, (660°) compelled me to adopt 
as a standard of comparison, between the different metals, and be¬ 
tween different masses of the same metal, a point indicated by the 
senses. A barely red heat in daylight was chosen, as least liable to 
be misapprehended. Many experiments have been made at tem¬ 
peratures both above and below this point; but as it is probable that 
the heated parts of boilers are seldom raised above a dull red heat, 
and that if they were so, their danger, or (perhaps we might say) 
their safety , would arise from the softness and yielding condition of 
the metal, it has been thought that for practical as well as theoretical 
purposes, the point above mentioned would be most interesting and 
important. The experiments to determine the period of greatest 
activity will show, that just below the point of visible redness in day¬ 
light, the greatest quantity of steam is generated in a given number 


7 


Experimental Inquiries respecting Heat and Vapor. 

of instants. Such at least is the case when the experiment is per¬ 
formed under ordinary atmospheric pressure. This point therefore, 
I have termed in the tables the comparable temperature. Many of 
the experiments with wrought iron were performed upon a piece of 
rolled boiler plate , 25 J inches long, by 7J broad, and T \ of an inch 
thick, affording a surface (including both faces, and all the edges) of 
three hundred and ninety five square inches. This was reduced to 
a coil, for the greater convenience in managing the experiments, but 
sufficient space was left for the free admission of water to every 
part of the surface. The first series was intended to exhibit the 
quantity of steam generated without particular reference to the time. 
The latter however was immediately noted on each occasion, but is 
not to be taken as the least time, in which the mass of metal em¬ 
ployed could impart its surplus heat to boiling water. It serves to 
show that no essential difference was discoverable in the amount of 
steam produced by metal of the same temperature, whether the lat¬ 
ter were immersed all at once, or only covered by degrees with the 
water, and that, consequently the portion of overheated surface which 
remained above the water, did not impart to the steam which ascend¬ 
ed, any appreciable quantity of its caloric, during the experiment. 

FIRST SERIES, 


With rolled iron, 395 square inches of surface—water at 212° Fall.; 
barometer 29.9 inches; the time marked by a pendulum beating 
seconds; temperature of the apartment from 80° to 85°. 


No. of experiment. 

Weight of metal in 
ounces avoirdupois. 

t n 

T3 

a 

o 

o 

o 

CO 

S3 

• H 

O 

£ 

H 

Weight of steam in 
ounces avoirdupois. 

Decimal part of an 
ounce of steam from 
each ounce of metal. 

No. of ounces of me¬ 
tal that produced 
each ounce of steam. 

Observed heat of the metal in day light. 

1 

144. 

40 

10.75 

.0746 

13.395 

Black heat. 

2 

144.25 

90 

10. 

.1109 

9.016 

Comparable or dull red in day light. 

3 

144.25 

90 

16. 

.1109 

9.016 

Do. do. do. 

4 

144.125 

90 

16. 

.1110 

9.008 

Do. do. do. 

5 

144,125 

90 

16. 

.1110 

9.008 

Do. do. do. 

6 

144. 

70 

16.5 

.1145 

8.727 

Slight incr’se in redness, plunged sooner. 

7 

144. 

150 

19.75 

.1371 

7.291 

Clear red, immersed by degrees. 

8 

144.25 

120 

20. 

.1386 

7.2125 

Bright red. 

9 

144. 

90 

21. 

.1458 

6.857 

Brighter red. 

10 

144. 

90 

22.5 

.1562 

6.400 

Very bright; metal yielding easily. 
























8 


Experimental Inquiries respecting Heat and Vapor. 

The 2d, 3d, 4th and 5th experiments, present a remarkable coin¬ 
cidence of results, and prove that at the temperature of comparison, 
nine pounds of wrought iron will generate one pound of steam, un¬ 
der atmospheric pressure. Subsequent series will show, that, but for 
the caution necessary to avoid waste, this effect might have been 
produced in twenty-five or thirty seconds, instead of the times above 
noted. 

SECOND SERIES, 


With wrought iron cylinders, 6 inches long, and 1.7 inches in diame¬ 
ter; surface, 38 square inches, including that of the hook ; water 
kept at 212°. 


■+-> 

cn 

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Ounces avoir 
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Ounces of ste 
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a ° © 

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HEAT OBSERVED. 

REMARKS. 

1 

62.5 

42 

4 

.0640 

15.625 

Black. 

( Iron immersed at 








l once. 

2 

62.5 

45 

4 

.0640 

15.625 

Do. 

Do. do. 

3 

62.5 

45 

5.25 

.0840 

11.904 

Do. 

Do. do. 

4 

62.5 

48 

5.5 

.0880 

11.363 

Do. 

Do. do. 

5 

63 

120 

7 

.1111 

9.000 

} Dull red; com- 
$ parative temp. 

Do. by degrees. 

6 

63 

120 

7 

.1111 

9.000 

Do. 

Do. do. 

7 

63 

120 

7 

.1111 

9.000 

Do. 

Do. do. 

8 

63 

120 

7 

.1111 

9.000 

Do. 

Do. do. 

9 

63 

80 

7.25 

.1150 

8.689 

Do. 

$ Do. quickly but 






l not at once. 

10 

62.5 

90 

7.75 

.1240 

8.064 

Fair red. 

Do. do. 

11 

63 

150 

8 

.1270 

7.875 

Do. 

Do. by degrees. 

12 

63 

150 

8 

.1270 

7.875 

Do. 

Do. do. 

13 

62.25 

100 

9.5 

.1365 

6.552 

Full red. 

Do. at once. 

14 

62.25 

120 

10.5 

.1686 

5.928 

Bright red. 

Do. do. 


The striking correspondence in the results of those experiments in 
the above series, which purport to have been made at the compara¬ 
ble temperature (No.’s 5, 6, 7, 8 and 9) with the analogous ones in 
the first series , render it evident that in this form, as well as in that of 
the plate, the amount of steam generated by any portion of wrought 
iron at a dull red heat, bears a direct relation to the weight of metal, 
being one pound of steam to every nine pounds of iron. 




















Experimental Inquiries respecting Heat and Vapor 


9 


THIRD SERIES, 

With cylinders of cast iron of different weights, and at different tem¬ 
peratures ; water at 212°. The surface exposed in each experi¬ 
ment, is indicated in a separate column. 



i 

2 


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s_ 

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G 

HEAT OBSERVED. 


REMARKS. 

o 

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0) 




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G 

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p-i ifj 

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cr 1 

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i 

60 

30 

2.25 

.0375 

26.666 

37.69 

Black. 

Immersed at once. 

2 

16S 

60 

6.75 

.0401 

24.888 

86.25 

Do. 

Do. 

do. 

8 

152 

80 

7. 

.0460 

21.714 

77.47 

Do. 

Do. 

by degrees. 

4 

60 

50 

3.375 

.0562 

16.000 

37.69 

Do. 

Do. 

at once. 

5 

168 

90 

14.25 

.0848 

11.789 

86.25 

Do. 

Do. 

do. 

6 

152 

135 

13.75 

.0904 

11.054 

77.47 

Do. 

Do. 

do. 

7 

60 

55 

5.5 

.0916 

10.909 

37.69 

Do. 

Do. 

do. 

8 

60 

55 

5.5 

.0916 

10.909 

37.69 

Do. 

Do. 

do. 

9 

168 

105 

15.5 

.0922 

10.838 

86.25 

Do. 

Do. 

do. 

10 

168 

106 

16. 

.0952 

10.500 

86.25 

Do. 

Do. 

do. 

11 

60 

60 

6.5 

.1083 

9.230 

37.69 

Low red in the dark. 

Do. 

do. 

12 

60 

55 

6.75 

.1125 

8.888 

37.69 

Do. 

Do. 

do. 

13 

60 

55 

6.75 

.1125 

8.888 

37.69 

Do. 

Do. 

do. 

14 

61 

90 

7. 

.1147 

8.714 

37.69 

C Comparable, (dull 
t red in day light.) 

| Do. 

by degrees. 

15 

168 

300 

19.5 

.1160 

8.618 

86.25 

Do. 

Do. 

do. 

16 

168 

300 

19.5 

.1160 

8.618 

86.25 

Do. 

Do. 

do. 

17 

61 

105 

7.25 

.1185 

8.413 

37.69 

Do. 

Do. 

do. 

18 

61 

105 

7.5 

.1229 

8.133 

37.69 

Do. 

Do. 

do. 

19 

61 

120 

7.5 

.1229 

8.133 

37.69 

Do. 

Do. 

slowly. 

20 

152 

300 

19. 

.1250 

8.000 

77.47 

Do. 

Do. 

do. 

21 

152 

300 

19. 

.1250 

8.000 

77.47 

Do. 

Do. 

do. 

22 

152 

300 

19. 

.1250 

8.000 

77.47 

Do. 

Do. 

do. 

23 

60 

70 

7.75 

.1291 

7.741 

37.69 

Brighter red. 

Do. 

almost instantly. 

24 

152 

300 

21. 

.1316 

7.238 

77.47 

Clear red. 

Do. 

gradually. 

25 

61 

90 

8. 

.1331 

7.625 

37.69 

Do. 

Do. 

in few seconds. 

26 

61 

120 

8.5 

.1393 

7.176 

37.69 

Do. 

Do. 

gradually. 

27 

168 

180 

23 5 

.1398 

7.149 

86.25 

Full red. 

Do. 

do. 

28 

60 

75 

8.5 

.1416 

7.058 

37.69 

Do. 

Do. 

at once. 

29 

151 

300 

22. 

.1457 

6.864 

77.47 

Do. 

Do. 

gradually. 

30 

61 

120 

9. 

.1475 

6.727 

37.69 

Bright red. 

Do. 

do. 

31 

152 

180 

29. 

.1908 

5.241 

77.47 

Do. 

Do. 

in few seconds. 

32 

60 

105 

11.5 

.1916 

5.217 

37.69 

Very bright. 

Do. 

rapidly. 

33 

152 

270 

32.75 

.2154 

4.641 

77.47 

Do. 

Do. 

gradually. 

34 

152 

360 

34. 

.2237 

4.470 

77.47 

Do. 

Do. 

slowly. 


It appears from the preceding table, that the least amount of steam 
given by any of the experiments, was that of No. 1, where, under 
the head of decimal parts , we find 3| per cent.; and the greatest 
amount was that of No. 34, where the same column exhibits 22 T \\ 
per cent. In the latter case, 4 r Vo lbs. of metal gave a pound of 
steam, while in the former, 26§ lbs. were required for that purpose. 

2 






























10 


Experimental Inquiries respecting Heat and Vapor. 

A comparison of the third series with the two preceding, will 
show that at the comparable temperature , cast iron is capable of 
generating more steam for each unit of weight in the metal, than 
wrought iron. It may possibly be found that the temperature of lu¬ 
minousness in the two kinds, is different. But from heating similar 
masses of the two, side by side in the same exposure, and observing 
no difference in the time of coming to redness, I have been led to 
attribute the difference to a difference in the specific caloric of cast 
and wrought iron ; a circumstance which would probably be suffi¬ 
ciently accounted for, by the difference in their constituent elements. 

The mean amount of cast iron to each pound of steam, in the nine 
experiments marked comparable , is 8 r 2 /oV lbs. We might probably 
assume 8J as the number, without material error. 

From the data above furnished, we may readily calculate the quanti¬ 
ty of steam, of atmospheric pressure, which would be generated by any 
known quantity of iron that should become red hot. Thus, should a 
boiler twenty feet long and thirty inches in diameter, with a returning 
flue one foot in diameter, be constructed of iron one fourth of an inch 
thick, the exterior shell would give a curved surface of 157 square 
feet, and as the specific gravity of good boiler iron is 7.770, it must 
weigh 10 pounds 2 oz. to the square foot. The whole exterior 
cylinder would therefore weigh 1582 pounds, exclusive of any al¬ 
lowance for rivets and for double thickness at the joints. The 
weight of the interior shell or due will be 63G pounds. As the fire 
is supposed to act on one half of the outer shell, and on the whole of 
the flue, there would, in case of the heeling of a boat, sufficiently to 

15S2 

throw all the water out of one boiler, be no less than 6364-“g—=1427 

pounds of iron exposed to the direct action of the fire, and liable to 
become red hot. By the first series , we see that one pound of at¬ 
mospheric steam will be generated from water at 212° by every 
nine pounds of iron, at a low red heat, in day light; consequently, the 

1427 

metal above supposed would be sufficient to produce —^—=158| 

Ibs. of steam from water at 212°, whenever a change of position 
should favor its influx in sufficient quantity to cover, either by actual 
submersion, or by violent agitation, the surfaces of the flue and lower 
arch of the boiler. To calculate the effect of this weight of vapor, 
we must compare its bulk with the steam-room left in the boiler. 
The whole interior capacity of the latter is but 82.4 cubic feet; but 




11 


Experimental Inquiries respecting Ileat and Eapor. 

in the condition of tilings now supposed, a small part only of this 
space is occupied by water. 

The bulk ol steam becomes known by comparing its specific 
gravity with that of the water from which it is formed. Thus, as¬ 
suming the specific gravity of common air, at G0° Fall, to be .00122 
of that of water at the same temperature, as determined by Biot & 
Arago, the specific gravity of steam compared with air at 60° being 
.4S1 to 1, the specific gravity of steam compared with water at that 
temperature , is .00058682. As 158f lbs. of water at 60° measure 
158.5 

-^2^=2.536 cubic feet, the atmospheric steam , which can be ob¬ 
tained from it will be=2.536~.00058682 —4321 cubic feet; which, 

4321 362 

divided by the capacity of the boiler, gives -g^ = 52g^ = 52f, 

nearly, for the number of atmospheres of pressure, supposing the 
whole to be condensed and confined in the single boiler, within 
which we have shown that it may be generated. This would give 
786 lbs. to the square inch. But upon the supposition that while 
heat continues to be applied to the boiler, from which the water is 
drained, its connexion with others remains uninterrupted, nearly the 
usual pressure will be maintained within it. This pressure may be 
stated at 8 atmospheres ; so that by adding the 52f derived from 
the over-heated metal we should have no less than 60-f atmospheres 
or 906 lbs. to the square inch for the resulting elasticity. This is 
upon the assumption that steam obeys the same law in regard to its 
relative bulk and elasticity, as that which governs atmospheric air. 
But if it do not follow that law, there is no probability whatever that 
the pressure would be less than in the direct ratio of the density. 

It is true that if only one boiler in a range were to become 
empty and exposed to excessive heat, at the same time, the quan¬ 
tity of steam just calculated, would be, in part, distributed through 
the connecting pipe, to the others, at the moment of its produc¬ 
tion, which would diminish in a measure the pressure in the over¬ 
heated boiler. It may be said on the other hand, that the over¬ 
heating of the outer shell will never be confined to the lower arch, 
nor to a single boiler in a range; and it is evident that the lower 
boilers in a boat must in the cases supposed want steam room in pro¬ 
portion as the upper want water; and that the connecting pipe could 
not, as generally constructed, convey away the steam so fast as it 





12 


Experimental Inquiries respecting Heat and Vapor* 

would be produced. The boiler which had been most remote from 
the wharf, has generally sustained the injury, in explosions that have 
occurred immediately after putting off. 

Before proceeding to the detail of experiments on other metals, I 
think it proper to present the following series of results, in which my 
main object was to ascertain, accurately, the rapidity of cooling of 
iron from incandescence down to 212°, taking into consideration the 
temperature of the water, both at the beginning and end of the ex¬ 
periment, its weight in some cases, and the relation, in all cases, be¬ 
tween the weight of metal and the amount of its generating surface. 
These experiments were performed in an apparatus similar to that 
described in my former communication, but furnished with an at¬ 
tached thermometer to mark with accuracy the temperatures attained. 
The result, as will be seen, is, that the times approximate to an in¬ 
verse proportion to the generating surface. This proportion will not 
be found to obtain, where part of the heat was employed in raising 
temperature, and a part in generating steam. The time demanded 
for cooling a given mass of metal from redness to 212°, by the latter 
process, must be greater than by the former, both because the tem¬ 
perature of the liquid, which is to receive heat, is greater, and the 
difference between it and the metal less, and because the surface of 
the iron is momentarily denuded of water and prevented from acting 
by a constant and uniform communication. The temperature, in a 
few instances, was calculated by multiplying the weight of water by 
the number of degrees through which it was heated, and dividing the 
product by the weight of metal multiplied into its specific heat. To 
the quotient was, of course, added 212°, the temperature at which 
the metal was withdrawn after every trial. 


Experimental Inquiries respecting Heat and Vapor 


13 


FOURTH SERIES. 

Showing the time in which iron, in a state of incandescence, may¬ 
be reduced to the boiling temperature, either by heating water from 
different points, by generating steam, or by both operations in suc¬ 
cession. 


S X 

a 

0 

U 

J3 £ 

03 

A tic 
£.S 

C 

1 

a 

»“H 

d 

tj 

G 3 

G +-> 

O 

*- a 
— 1 0 

1 

d 

u 

<D 

a* 


S CO 

e % 

£ 

0 

^ s 

75 c 

cs p 

b» a 

a 


£ 

a. 

X 

03 

d 

& 

U-. 

O 

O-i 0 

O so 

C be 

0 Sc 

i. 03 

3 -Q 

(V 

O 

u 

4 -> 

d _4__> 

0 

ime in passin 
incandesce 
212°. 

ated tei 
ture. 

Remarks on observed tempera¬ 
tures. 

*5° ro 

Q ^ 

A*—. 

0 

6 

rC 

b0 

’3 

.~ a) 

75 S 

03 O 

Oh +-> 

s * 

0 — 

0,-0 
s « 

3 

O 

13 



fc 

£ 

03 

E» £ 

' 

H 

0 


' N . 


lbs. 

oz. sq.in. 

0 

O 

ll 

0 


>> O c 








QO . 

c® c 

1 

26 

1 : .513 

60 

138 

77 

1805 

Very bright red. 

•3 .•'ifi I 

2 

unc. 

1 : .513 

60 

140 

81 


Comparable. 

il2 1 

3 

unc. 

1 : .513 

120 

212 

71 


Clear red. 

0.5 <*> j 









• ^ ^ 









>> O G 
O'- 

4 

15 

1 : .515 

55 

190 

126 


Bright red. 

O 

a 0 cr 

5 

21.5 

1 : .515 

60 

144 

117 

1801 

Very bright red. 

P H W V 

6 

unc. 

1 : .515 

60 

212 

114 


Bright red. 

- 

1 —_ 

7 

11 

1 : .515 

76 

180 

95 

1218 

Above comparable. 

o.S^ J 









«—< N 5 

~8 

unc. 

1 : .625 

60 

100 

90 


Very bright. 

>» O G 

O _ .s 

9 

10 

1 : .625 

80 

212 

112 


Do. 

C CO _i. 






C Very bright, continued red in 

O _ Gr V. 

U Cfl ( 

10 

unc. 

1 : .625 

212 

212 

128 


2 the water 82", and ebullition 

*. « »o 






£ ceased in 46" afterwards. 

2 c N 
(J- s M ^ 

11 

14 

1 : .625 

180 

212 

110 


Bright red. 

C 5 

11 

12 

s-. 

0 

G 

1 : 2.75 

60 

212 

23 


Comparable. 

g ® 

13 

U 

O) 

I : 2.75 

100 

212 

23 


Do. 

> 'H ci 

> rf 

0 >- 

O „ 3 1 

14 

H-J 1 . 

2 "G 

1 : 2.75 

128 

212 

33 


Full red. 

15 

£ 0 
> 

1 : 2.75 

175 

212 

41 


Bright red. 

a) ^4 wj > 

16 

O O 

1 : 2.75 

180 

212 

25 


Comparable. 

JH £ a 
& . ■" 

-o fl O' 

17 

18 

>» 0 

1 <*-> 

1 : 2.75 

1 : 2.75 

212 

212 

212 

212 

25 

28 


Do. 

Do. 

<D <Ji 

*—• CQ 

OHg 

P 3 co co - 

19 

G 

C 3 

3 

a 

1 : 2.75 

212 

212 

36 


Full red. 

A a r; "1 

20 

1.375 

1 : 1.14 

“32“ 

133 

20 

1462 

Clear red. 

'bJD £f> O 


127 

19 

1288 

( Rather less red, but above 

•53 .5 .2 

21 

1.375 

1 : 1.14 

40 

£ comparable. 

^ *2 0 

~ u 

22 

1.375 

1 : 1.14 

72 

172 

21 

1449 

Clear red. 

P £ G 

23 

1.375 

1 : 1.14 

100 

212 

25 


Do. 

|« u “ 

24 

1.375 

1 : 1.14 

112 

212 

30 


Do. 

fe G QO 

25 

1.375 

1 : 1.14 

126 

212 

31 


Do. 

C^ rH 

26 

1.375 

1 : 1.14 

148 

212 

36 


Do. 

UNO 

27 

1.375 

1 : 1.14 

168 

212 

43 


Do. 

.£ 0 a> 
A® 0 

28 

1.375 

1 : 1.14 

190 

212 

75 


Do. 

£ 

29 

1.375 

1 : 1.14 

200 

212 

77 


Do. 

Q .2 S J 

30 

1.3751 1 : 1.14 

212 

212 

78 


Do. 
















































































14 


Experimental Inquiries respecting lleat and Vapor. 


FIFTH SERIES, 

With hollow cylinders of copper, presenting 149 square inches ol 
generating surface—water kept at 212°. 


-*2 

C 

<V 

s 

,5 an 

_ "3 
a g* 

© -3 

2 .Ss 

C fj 

a 

© 

£ 

c3 

CD 

ut of an 
;team to 
of metal. 

s a 

« 03 

a <d 

CD co 

2 <o 



a. 

x 

© 

o 

o 

5? 

o 

©H > 

o a 

■©> cn 

32 © 
bfi g 

« s 
^ ° 

© 

to 

.2 

© 

2 

P 

Ounces of 
produi 

Decimal pj 
ounce of s 
each ounce 

© 

° 8 
a> 3 
© o 

3 X 

= u 

o © 

Heat observed. 

Remarks. 

1 

158.50 

75 

9.875 

.0636 

16.050 

Black. 


2 

158.25 

50 

10.5 

.0663 

15.071 

Black. 


3 

157. 

70 

12.25 

.0780 

12.816 

( Reddish by dusk, but 
( not in day light. 


4 

159. 

70 

13.5 

.0S46 

11.777 

Do. 


5 

159.25 

73 

14.25 

.0895 

11.175 

Comparable dull red. 

\ Immersed 
( at once. 

G 

159. 

45 

14.25 

.0896 

11.158 

Do. 

7 

158. 

55 

14.5 

.0911 

10.896 

Do. 


8 

156.75 

66 

14.5 

.0925 

10.810 

Do. 


9 

158.75 

75 

14.75 

.0929 

10.762 

Do. 


10 

159.75 

75 

15. 

.0939 

10.650 

Clear red. 


11 

157.5 

65 

15.25 

.0967 

10.327 

Do. 


12 

157.75 

70 

17.25 

.1093 

9.145 

Bright red. 



The mean amount of metal to the ounce of steam in the five ex¬ 


periments marked comparable in the above table, is 10 f 9 /^ ounces, 
which may be assumed as 11 without sensible error. 


SIXTH SERIES, 

To determine the quantity of steam yielded by given weights of cast 
brass at red heat, when plunged into water at 212°. 


a 

© 

.£ 

to 

CO 

2 

CS 

O . 

-2 

2 © 

O 3 

a 

,__ (C 

c3 © 



s 

03 

u 

a 

CD . 
tn -O 

c3 a 

-+-» •*— > 

0) to 


4 « 

<© 

o to 
(D 

o 

© 

C4-. a 

•4—, 

a '■g 

e 'o 



Cl, 

X 

© 

o 

u_i ^ 

o a 

P 

2 ° 
oD 

© 

03 

© 

O 3 

03 r 2 

QJ O 

2 * 

° 8 

,£ § 
fee § 

"o © 

° u 

03 O 

© 3 

© o 

Heat observed. 

Remarks. 

o 

Z 

“© 

£ 

2 

—j 

o 

L® a 

pt a 

§ 8 

O o 



1 

176 

70 

15.75 

.0895 

11.809 

^ Red only in 
l the dark. 

Immersed at once. 

2 

176 

120 

16.5 

.0943 

10.666 

{ Comparable, 

^ (dull red.) 

Do. by degrees. 

3 

175 

60 

16.75 

.0958 

10.448 

Do. 

Do. at once. 

4 

176 

105 

17. 

.0966 

10.353 

Do. 

Do. more gradually. 

5 

175 

120 

17.25 

.0985 

10.145 

Do. 

Do. slowly. 

6 

175 

120 

17.25 

.0985 

10.145 

Do. 

Do. Do. 

7 

175 

180 

18. 

.1028 

9.722 

Clear red. 

Do. Do. 

8 

176 

75 

19. 

.1085 

9.263 

Full red. 

Do. at once. 

9 

176 

120 

22. 

.1250 

8.000 

Bright red. 

Do. gradually. 









































15 


Experimental Inquiries respecting Heat and Vapor. 

The five experiments which were made at a dull red heat in day 
light, and which were therefore marked comparable , prove that, on 
an average, one pound of steam requires 10 pounds of cast brass 
of that temperature for its production. It was observed that the vio¬ 
lence of agitation, when brass was employed, appeared to be much 
greater than when similar masses of iron were the subjects of experi¬ 
ment. This was attributed to its higher conducting power. A repe¬ 
tition of this series might not exhibit precisely the same results, un¬ 
less the specimens employed should have the same proportion of in¬ 
gredients and the same specific gravity. 

SEVENTH SERIES, 


With ingots of standard silver, of various weights, from 21J to 195J 

ounces avoirdupois. 






o 

o A 



a 

g 

*n 

£ s. 

g o 

a 

o 

a 

a 

o 

w o 

»—< 

O ^ 

o s 
s a 

~ & 

& 

cs 

•4-J 

s ^ 



<D 

Oh 

* 

o 

> 

o Cl 

o 

0) 

« o 
o a 

4J T3 

C3 

4-» O 

Cft 

° CJ 

Heat observed. 

Remarks. 

<z> 

-4-> m 

a 

o: P 

Vh d 




o 

rC 0) 

Oh 

S O 

P 5 



6 

• § 

g 

(D 

£ 

a © 




Z 

£ ° 



CL, 

O o 



1 

195.5 

120 

10. 

.0511 

19.550 

{ Comparable , 

(dull red.) 

^ Immersed by de- 
\ grees. 

«> 

26.5 

30 

1.375 

.0519 

19.272 

Do. 

Do. at once. 

3 

26.5 

33 

1.5 

.0566 

17.666 

Do. 

Do. Do. 

4 

26.5 

30 

1.75 

.0660 

15.143 

Clear red. 

Do. Do. 

5 

26.5 

32 

1.75 

.0660 

15.143 

Do. 

Do. more gradu- 
( ally. 

0 

41.2 

50 

3.0625 

.0740 

13.453 

Do. 

Do. at once. 

7 

41.2 

55 

3.125 

.0758 

13.120 

Full red. 

Do. Do. 

S 

195.5 

130 

15. 

.0767 

13.033 

Do. 

Do. gradually. 

9 

21.5 

30 

1.75 

.0814 

12.286 

Do. 

Do. at once. 

10 

41.2 

68 

3.5 

.0849 

11.771 

Do. 

Do. gradually. 

C Do. at once; sil- 

11 

26.5 

30 

2.5 

.0943 

10.600 

Bright red. 

< ver beginning 
( to soften. 


From a comparison of the three experiments marked comparable , 
in the above table, it appears that about IS T \\ pounds of standard 
silver will be required for generating one pound of steam. 


















16 


Experimental Inquiries respecting Heat and Vipor. 

EIGHTH SERIES, 

With an ingot of pure gold, weighing 14 lbs. 8J oz. avoirdupois,* 
and other circumstances as in preceding series, the following re¬ 
sults were given. 


No. of experiment 

Weight of gold in 
oz. avoirdupois. 

Time in seconds. 

Weight of steam 
produced. 

Weight of steam to 
unit of metal. 

Ounces of metal to 
unit of steam. 

Heat of metal. 

Observations. 

1 

232.25 

100 

2 oz. 

.0086 

116.125 

Red in the dark. 

C The water had remained expo- 
< sed a short time, and probably 
( lost a few deg’s before this exp. 
Plunged by degrees. 

2 

232.25 

120 

5 “ 

.0215 

46.450 

Comparable. 

3 

232.25 

125 

6 “ 

.0258 

38.708 

Comparable. 

Do. 


The mean, of the two experiments, made at the temperature of 
comparison, is 42 T Yo pounds of metal to each pound of steam. The 
extremely low specific heat of gold, renders necessary every precau¬ 
tion formerly detailed, in regard to avoiding loss of temperature in 
the water between two successive experiments, and also demands 
peculiar accuracy and dispatch in the process of weighing. After 
all the efforts, which were made to insure a correct result, it may 
have happened that a few degrees of heat, in the gold, were expen¬ 
ded in raising temperature , and a corresponding deficiency in the 
quantity of heat of elasticity may have been the consequence. 

The following summary exhibits a comparative view of the several 
metals submitted to trial, as shown in the preceding series, indicating 
the mean result of those experiments in each series which were 
made at the comparable temperature. 

From all the preceding series it appears that at comparable tem¬ 
perature, each pound of steam requires for its production of 


Cast iron, 

8* 

pounds 

Wrought iron, 

- 9 

cc 

Wrought copper, 

10- 3 - 5 - 

iv 100 

(( 

Cast Brass, 

- 10- 9 - 6 - 
1U 100 

u 

Standard silver, 

18- 8 - 3 - 
1U 1 1)0 

a 

Pure gold, 

- 42 - 5 - 8 - 

1 0 0 

u 


If the temperature assumed for comparison be precisely as much 
above 212° as is equal to the number of degrees of heat, which be- 

* The above mentioned mass of gold, at the mint valuation of TgV cents per grain, 
was worth $4105.448. For the use of this, as well as of several ingots of silver, and 
for other conveniences in these experiments on the precious metals, I am indebted 
to the politeness of Dr. Moore, superintendent—Mr. Eckfeldt, chief coiner—and 
other officers of the United States’ Mint. 




















17 


Experimental Inquiries respecting Heat and Vapor. 

come latent in water while it passes into steam, it is evident that any 
substance at comparable temperature, and possessing the same spe¬ 
cific heat as water , would generate its own weight of steam in cool¬ 
ing down to 212°. But if its own specific heat be less than that of 
water, its weight must be proportionally increased, and then the 
effect of cooling will be the production of the same weight of steam 
as before supposed. Hence as the specific heat is directly propor¬ 
tional to the quantity of steam which a given weight of metal would 
produce, the latter may, at a known temperature, be assumed as a 
measure of the former. By the following comparison it will be ev¬ 
ident that the temperature adopted in these experiments was nearly 
identical with that which I have above alluded to, and which exceeds 
212°, by the amount of latent heat (990°) in a unit, by weight, of 
steam. 


Steam to the unit of metal. 

Specific heat. 

Iron, 

.1111 

.1100 

Petit & Dulong. 

Copper, 

.0907 

.0949 

if (( 

Brass, 

.0940 

.1100 

Dalton. 

Silver, 

.0532 

.0557 

Petit & Dulong. 

Gold, 

.0236 

.0298 

« a 


It must be observed that the above statements of specific heats, 
taken from Petit and Dulong, are those of the mean effect from 0° 
to 100° centigrade. That of silver, for example, is .0557 within 
these limits, but if the mean specific heat found by them from 0° to 
300° cent, be adopted, it will come somewhat above the result of 
my experiments, that is .0611. 

The method which has thus been adopted, adds another to the 
means heretofore employed for determining the specific heat of many 
solid and gaseous substances, or at least of verifying the results of 
former methods. The three modes, just alluded to, are those of 
mixture , of melting ice , and of cooling in air , the last in particular 
seems liable to many objections on account of the different conduct¬ 
ing and radiating power of the bodies, and the different natures of 
the surface which may be given to each, whereby the time of cooling, 
which is made the measure, will be exceedingly variable. 

The calorimeter, of Lavoisier, is not regarded as correct in its 
indications, on account of the subsequent congelation of a portion 
of the ice, melted by the hot body, and the rise of temperature in 
water by mixture , involves the necessity of considering the increase 
of temperature, in the containing vessel, together with its separate 

3 


18 


Experimental Inquiries respecting Heat and Vapor. 


specific beat, before any accurate result can be anticipated. Tbe 
method of generating steam from an apparatus ke]3t at a uniform 
temperature, and by means of bodies of known superior temperatures , 
is, I conceive, less liable to objection from any of these sources of 
fallacy. Tbe only modifying cause, which deserves much attention, 
is tbe barometric pressure during the experiment, which involves also 
a consideration of the specific heat of steam under different press¬ 
ures, but as this source of error may be obviated by performing ex¬ 
periments at uniform pressures, we need hardly take it into view, in 
estimating the general correctness of the mode now proposed of 
verifying the specific heats of bodies. 

By knowing at what temperature we plunge a piece of metal un¬ 
der boiling water, the weight of the metal, and its mean capacity for 
heat, we may readily infer, from what is known of the quantity of la¬ 
tent heat in the unit by weight of steam, what weight of the liquid 
will be boiled off while the metal is reduced from a superior tem¬ 
perature down to 212°. . 

Thus let the temperature of the metal above 212° —t 

Its weight —w 

Its mean capacity between 212° and the known temperature ~c 

The latent heat of atmospheric steam —l 

The weight of steam which the metal can produce =s 
tew 

Then will s—-j- Thus, suppose ^=2000°, c=.l111, w= IGoz. 

tew 2000 X. 1111 X1G 

and Z=990°, then we shall have — - 000 -= 3,571 


ounces. 

From the above formula we derive immediately an expression for 

the temperature when all the other elements are known ; for ls = tcw, 
Is 

whence t=—> so that when we would determine the actual tern- 

perature of a body above 212°, whose specific caloric has been care¬ 
fully ascertained, we have only to find what weight of vapor it will 
produce in coming down to the point of ebullition; multiply this by 
the latent heat in steam , and divide the product by the product of the 
weight of heated matter multiplied by its specific heat. Upon the 
basis of this proposition I have constructed an instrument called the 
steam pyrometer , to be applied to the measurement of heat in incan¬ 
descent metals, coals and furnaces, to mark the melting point of metals, 
to verify the results presented by other instruments employed in similar 
operations, and to answer some other practical and scientific purposes. 





Experimental Inquiries respecting Heat and Vapor. 19 

The several series of experiments heretofore detailed, in relation 
to the actual quantity of vapor yielded by red hot metal, and to the 
time employed in producing it, have furnished some of the data for 
calculating the effect of overheating a steam boiler and immediately 
furnishing it with water. It is evident, that even with the same tem¬ 
perature in the metal, certain circumstances may exist at one time 
which shall modify the result exhibited at another. The tenth ex¬ 
periment in the fourth series,* * in which 60 ounces of metal continued 
red for 82 seconds, beneath the surface of boiling wafer, and after¬ 
wards occupied 46 seconds in parting with the excess of heat above 
212° which then remained, might.possibly lead to the inference, that 
the quantity of heat disengaged in the former part of the operation 
was at least twice as great as that, which was given out in the latter. 
This would imply that the temperature, (omitting difference in spe¬ 
cific heat,) had been at first three times as much above 212°, as it 
was at the moment when redness disappeared. But the whole of the 
fourth series, as well indeed as all the other series heretofore given, 
had manifested in the performance of the experiments, a much more 
vigorous action subsequent to the disappearance of redness, than be¬ 
fore that period. It was therefore necessary, in order to obtain some 
degree of clearness on this head*, to perform several courses , each 
consisting of a number of series of experiments. 

The general fact that red hot metal repels water, or at least does 
not appear to exercise upon it any contiguous attraction, has long 
been familiar. The smith who plunges a piece of iron, at a white 
heat, into his trough, sometimes sees with astonishment that scarcely 
any agitation of the liquid occurs for the first few seconds; and he 
perceives that this is not due to the coldness of the water, requiring 
it to be heated up to boiling temperature, before it can undergo the 
agitation consequent upon the formation of steam; for by plunging 
another piece of metal at a black heat into the same liquid, the ac¬ 
tion becomes immediately and distinctly perceptible. 

When water is sprinkled upon a stone plate, even below redness, 
the drops are often observed to roll, apparently with little or no adhe¬ 
sion, from side to side, until slowly dissipated, or until they at length 
become attached and finally disappear, amidst a rapid ebullition and 
a violent hissing noise. 


* See Vol. XX, p. 311, of this Journal. 

* • 


4 





20 


Experimental Inquiries respecting Heat and Vapor. 

In the use of his generators, somtimes at the temperature of red¬ 
ness, Mr. Perkins had occasion to notice the fact above described, 
and to observe that the repulsion, between the metal and the water, 
sometimes becomes intense, amounting to a force greater than that of 
the elasticity of the steam, and that a small pipe heated red hot, might 
become entirely choked up, so to speak, with caloric, and incapable 
of transmitting any water or steam. 

It may also be mentioned, that Klaproth has performed some ex¬ 
periments on a small scale, illustrative of one part of the subject now 
under consideration. But they seem to have given rise to some 
erroneous deductions in regard to the action ol metal. It appears to 
have been inferred, that, as in cooling his spoon down from a white 
to a black heat, he passed from the time of AO" to 0" in the evapora¬ 
tion of six drops,—he had actually arrived at a point where the action 
of metal upon water would be instantaneous. 

From his experiments, and those of Perkins, it has likewise been 
inferred that the point of incandescence is that from which the repul¬ 
sion of water from- the surface of metal commences ; and that above 
redness, the augmentation of temperature is always attended by a cor¬ 
responding diminution in the rapidity of evaporation. An opportunity 
will perhaps be embraced in a future paper to recur to these opinions. 

The mode of performing the first of the following courses of ex¬ 
periments, was by procuring a basin of wrought iron about eight 
inches broad, one inch and three fourths deep at the center, and one 
fourth of an inch thick, made from a piece of rolled iron, and weigh¬ 
ing three pounds and a half. This was heated, either over a spirit 
lamp, with an argand burner, in a stove of anthracite, capable of 
maintaining a heat near whiteness, or at a forge fire, urged by a pow¬ 
erful bellows. When deemed sufficiently hot, it was withdrawn from 
the fire, and care being taken that no dust or ashes adhered to the 
surface, a measured portion of water was laid upon the center, the 
time from the moment it struck the metal till the last drop dis¬ 
appeared being carefully noted from an accurate time keeper, and 
recorded by an assistant. The temperature of the water was marked 
by a good thermometer, or was kept boiling by remaining constantly 
over the fire during a whole series. The trials were continued as 
long as the metal remained hot enough to produce vapor of atmos- 
phoric elasticity. The proceeding has rendered it highly probable, 
that the late ol cooling after the period of most rapid action has 
been attained, varies considerably from that which precedes, and 


21 


jljZ iperimental Inquiries respecting Heat and Vapor. 

— • > 

that possibly different stages of rapidity will be discovered, in differ¬ 
ent parts of the series following the time of most rapid vaporization. 


First course, comprising twelve series. 


Exhibiting the times in which given quantities of water of known 
temperature, may be successively converted into vapor, while the iron 
which produces it is cooled from redness to the point of ebullition. 


to 

0 ) 

o 

6 

o 

o 

d 

o 

o 

o 

o 

O 

O 

o 


“O 


33 

-a 


"C 

-a 



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o 


o 

o 

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o 

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o 

0) 

to 

•s 

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oo n 

o 

os 23 

&22 

K 5 • 

00 2! 

o 

§ 22 

00 to 

oo 22 

07 • 

co i2 

iO 

£ 22 

00 • 

00 w> . 

J= 

S f* 

■M 2 


— G 

— < a 


« a 



pH 



CJ 

o ~ 

• M 

. V 

• <D 

* 0) 

• 

. <x> 


• o 

o O . 

o <y 

O 

oz 

(V 

mLZ 

GO X 
• rv. 

O &> 

s 

o c 

,2 C 

33 S 

o £ 

.2 

o a 

33 .2 

-g £ 

33 S 

£ s 
• • —« 

-c 5 

N 

^ a 
n -c: 

c 

—‘ o 

N 

O a; 

N 5 
o — 

N o 
<= -O. 

§ 1. 

n 53 

° a. 

8 I 

o I 

8 £ 

o oj 

m ^ 

2 S. 

ii 

Cl 

to wi 

Qj r—i 

*M Q- 

* 

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oo x 

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OO X 

00 

• ¥<, 

7 * 

1 x 

y 

• PC 

2 03 


r2 ® 

_ « 

2, 03 

2. « 

fH O 

O 

H a) 


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• lO 

• h* 

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o oo 

o io 

o a 


<v cz 

o co 


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O P-! 

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to 


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33 


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pH 

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M 

CO 

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c© 


oo 

Ci 


^■H 



a 

II 

II 

II 

a 

II 

II 

// 

II 

II 

II 

ii 

1 

50 

105 

93 

173 

126 

134 

121 

66 

111 

78 

66 

80 

2 

55 

25 

23 

19 

14 

15 

16 

18 

13 

12.5 

17 

37 

3 

176 

15 

12 

9 

9 

6.5 

7.5 

9 

9 

5.5 

7.5 

14.5 

4 


21 

14 

14 

11.5 

10 

9 

9 

9 

7.5 

7 

9 

5 


31 

19 

17 

14.5 

14.5 

12 

11 

10 

9 

6 

6.5 

6 


41 

25 

22 

17 

16 

15 

14 

11.5 

11 

5.5 

6 

7 


69 

30 

24 

19.5 

19.5 

16.5 

15 

15 

14 

5.5 

5.5 

8 


150 

43 

28 

21.75 

20 

19 

19 

17 

14.5 

5 

6.5 

9 



57 

37 

26 

27 

22 

20 

19 

17 

5 

7 

10 



67 

50 

31 

30 

26.5 

22 

23 

19 

5.5 

8 

11 



135 

63.5 

38 

38 

30 

25 

27 

22 

5.75 

8 

12 



99 

49 

49 

39.5 

31 

30 

24 

6 

8.5 

13 




174 

70 

66 

54 

38 

41.5 

25 

7 

9.5 

14 





89 

99 

72 

45 

50.5 

33 

7.5 

11 

15 







107 

•68 

72 

40 

8 

11.5 

16 








95 

93 

50 

13 

13 

17 








190 

183 

82 

18 

14 

18 

19 

20 
21 

22 

23 

24 

25 










135 

20 

15 











22 

15.5 











25 

34 

17 

19 











42 

22 











50 

26 











83 

30 











140 

36 

44 

26 












59 

27 












89 

28 

29 

: 


• 








i : 

156.5 


RESULTS. 


1st series. 5f oz. generated in 281" 
2 intervals, 60" each 120 


2d series. 4 oz. generated in 457" 
7 intervals 10" each 70 


whole time of the series, 401 


whole time of the series 527 
































































22 


Experimental Inquiries respecting 


Heat and Vapor. 


3d series. 2f oz. generated in 518" 
10 intervals, 6.5" each 65 

4 

whole time of the series 583 

4th ser. If oz. generated in 727.5" 

12 intervals, 6.8" each S2.5 

.j 

whole time of the series 810 

5th ser. If oz. generated in 536" 

13 intervals, 12.0" each 169 

whole time of the series 705 

6th ser. If oz. generated in 534.5" 

13 intervals, 10.8" each 140.5 

whole time of the series 675 

7th ser. If oz. generated in 567" 

14 intervals, 10" each 140 

whole time of the series 707 


8th series. 2f oz. generated in 695' 
16 intervals, 6" each 95 

whole time of the series 791 

9th ser. 2f oz. generated in 724" 
16 intervals, 11" each 176 

whole time of the series 900 

10th ser. 2f oz. generated in 598.5" 
17 intervals, 16" each 271.5 

whole time of the series 670 

11th ser. ly 9 e-oz. generated in 613" 
24 intervals, 7" each 168 

whole time of the series 781 

12th ser. Iff oz. gener’d in 780.5" 
28 intervals, 8.2" each 230.5 

whole time of the series 1011 


As the water covered generally but a small part of the surface of 
the basin even at the commencement of the experiment, the heat in 
the latter terms of each series, must have been furnished to the water 
more slowly than in the preceding terms, both on account of the 
diminution of difference between the metal and the liquid, and on 
account of the necessity of depending on the conducting power of 
the metal, to bring the heat from the exterior to the center of the 
basin. Hence we might expect to find the terms obeying some law 
of geometrical progression. If we examine the last seven or eight 
experiments in each series, we shall clearly perceive such a progres¬ 
sion. Omitting the last of each column, as presenting anomalies 
obviously derived from the final disappearance of vaporization, and 
the substitution of mere evaporation , we may divide the last number 
but one, by that which precedes it; this latter, by the next preceding, 
and so on, until we obtain five quotients. These quotients will con¬ 
stitute the ratios of the series, at the particular points where the ex¬ 
periments took place. The mean results for each series may then 
be obtained in the usual mode. But it will soon be perceived that if 
we extend the divisions beyond five or six, the ratio will be essentially 
varied in its character, and the series, in some instances, becomes 













23 


Experimental Inquiries respecting Heat and Vapor. 

almost exactly coincident with an arithmetical progression. Thus the 
12th series, from the 11th to the 20th experiment, inclusive, may 
be regarded as composed of the numbers 8, 9, 10, 11, 12, 13, 14, 
15, 16, 17, while from the 23rd to the 2Sth, we have 26, 30, 36, 
44, 59, 89, yielding the ratios ff = 1.153, f§ = 1.200, ff = 1.222, 
£f = 1.341, and ff =1.508, and the mean of all these ratios is 1.285. 

By similar operations applied to the concluding part of every series 
in this course except the first and second, we obtain the following 
mean ratios for the several series respectively, viz. 


for the 

3rd 

series 

1.290 

a 

tt 

4 th 

tt 

1.334 

a 

a 

5th 

tt 

1.276 

a 

tt 

6th 

it 

1.302 

tt 

tt 

7th 

a 

1.270 

it 

tt 

CO 

cr 

tt 

1.308 

tt 

tt 

9th 

tt 

1.285 

it 

a 

10th 

a 

1.292 

a 

• it 

11th 

tt 

1.316 

a 

a 

12th 

it 

1.285 


If we would know the mean of all their mean ratios, we have but 
to divide their sum by 10, the number of series considered, whence 
w T e obtain 1.296 for the general ratio of this part of the several se¬ 
ries. It will, however be remarked that the five ratios belonging to 
the 11th series are themselves in geometrical progression, whose 
mean ratio is 1.07. 

In order to present to the eye the whole range of experiments in 
some of the series, I have adopted the method of curvilinear projec¬ 
tion, assuming as the unit of vapor, the amount actually employed at 
each trial, and as the unit of time, the number of seconds taken to 
vaporize it, at the period of most rapid action. Representing these 
units by equal vertical and horizontal lines respectively, the relative 
time of action in each experiment marked on the line a c, is denoted 
by the dotted lines, a d, eg , he. Figs. 1, 2 and 3. Regarding ab 
as a constant quantity, we have the portions of time above the rnini- 
mum , represented by that part of each vertical which is above the 
tangent bf. It will be seen by Fig. 1. that the arithmetical series 
exists in the 6th, 7th, and 8th experiments. Fig. 2d. shows the 
same feature at the 17th 18th, and 19th, while the 12th series, rep¬ 
resented by Fig. 3, shows a straight line from No. 11, to No. 20, as 
already stated. See the plate at p. 71. 


24 


Experimental Inquiries respecting Heat and Vapor. 


The next course of experiments was performed on a more extend¬ 
ed scale, by using a cylinder of cast iron about seven inches long, 
and three inches in diameter ; having at one end a cylindrical hole 
nine tenths of an inch in diameter, and three and three quarters of an 
inch in depth, concentric with the axis of the cylinder, and of course 
penetrating below the centre of the mass. The weight of the cylin¬ 
der was about ten pounds. This cylinder, heated to redness, was 
placed on the solid base, and the water was deposited from a suit¬ 
able measuring tube, in the hole at the upper end, due care being 
taken to clear the interior surface of scales and dust at the moment 
it was withdrawn from the fire. In this course, the red heat was 
maintained for a much longer period than was practicable with the 
rolled plate, when withdrawn from the fire. The time when redness 
disappeared, was generally noted, and is marked b against the 
number of seconds registered, at the experiment where it occurred. 
The minimum time is indicated in like manner by m. 

Second course, containing nine series. 


To exhibit the rate oP decrease, the time of most violent action, 
and the subsequent increase of time of vaporization in a cylinder of 
cast iron, employing an equal quantity of water at each trial in the 
. same series. 


< 

X 

c* O 

<D . 


- N cc 

w d) — 

£-c 

A u«5 

-i 2 

5 a 4> 

c 

. P 

3 £ ~ 

.2 £ 

“ £. 
c ~ 

w ° 

CJ m 

cn a 

• • 2 
g 0.0 

GO <u 

» c 

— X! 0) 
- 2 M 

cn w etj 


O 0 

der < 
peril 

— c 

C 4) 

“O r 

-a £ % 

oo CO 

6 


>/ • 

1 

31 

2 

30 

3 

30 

4 

30 

5 

31 

6 

34 

7 

30 

8 

33 

9 

34 

10 

29 

11 

27.5 


a T3 


<v 


a ,a 
• ■—« 


N 

O 

GO 


— 

O 

> 

a 

o 




-3 


26.5 

26 

26 

26 

26 

25 

24 

24 

22 

21 

19 


« 3 

„ d 

s- a 

<V 1) 

TO •“** 

o - 
. 

o a 
'T o 


c\ 

w 

CD . 



T3 

CO 


27 

27 

24 

23 

23 

20 

20 

19 

17 

15 

13 


4th Series, 1-8 oz. of water, at 
190°. Iron bright red. 

5th series, 1-8 oz of water, at 
i90°. Iron bright red. 

6th series, 1-8 oz. of water, at 
200°. Iron near whiteness. 

7th series. 1-8 oz. of water, at 
200°. Iron nearly white. 

// 

// 

// 

U 

14 

14.5 

18 

20 

13 

14 

16 

20 

12 

14 

16 

19 

11.5 

14 

16 

18 

10.5 

14 

15.5 

17.5 

10.5 

13 

15 

17 

10.5 

12 

14.5 

17 

10 

11 

14 

17 

10 

11 

13 

17 

10 

12 

12 

16 

10 

11 

12 

15 


S 

tT g *2 

£ -o 3 
« <o “ 
> <u 

!so 

O 

• S' 3 £ 

N - 
O - C 


T be C 

- S\S-g 

~ S3 Urn 

CD > 

_ # ' r C 

— O c 

c a o 

00 


27.5 

28 

34 

39 

30 

33 

22 

20 

18 

17 

17 


17 

17 

15 

15 

14.5 

14.5 

14.5 . 
13 
13 
12 

11.5 





















Experimental Inquiries respecting Heat and Vapor 


25 


TABLE CONTINUED. 


1 

X 

w V) 

a> a) 

x 

<U 

c « 

•“ X 
a u 

O ca 

, ol water, ar 
, lion red hot 
in the fire. 

of water, at 
y bright red. 

-4-* • 

« g 

CO *2 
£ 

° S3 

» 

r» 

S-. 

<D • 

| 2 

o £ 
hft 

d 

«\ 

u 

o 

•4—> • 

a 

£ « 

°x 

• hr) 

. of water, at 

ir whiteness. 

of water, at 

u ly white. 

c. ot water, at 

rapid ebulli- 

whole series. 

« bio 

u.S 
o x 

I s 

°3 

• ro 

’55 « 

«p c_ 

« ° 

O Eft 

_ w 

N Cl 9 
o * — 

• j= S 

8 I 

co a 

~ 2 

n e 
o u 

t § 

N ‘S 

O .Q 

00 a 
• o 

i - 1 

o 

00-° 

-j 

N Z 
c i 

°? c 

O 

o & 

GO ~ 

r-> 

•""* c 

O j- <U 

CD — -S _ 

7 a. “ 2 
d .5 D 

N —< 

C 3 

CO 

^ <D 

” 5 

" C3 p* 

c/j qj ,5 



CD 

CD 

c/> 

0) 

cK l “ l 
<D 

{/, 1 

O) 

rr. ^ Z > 

O ^ x*- 

o 

o ta 


CD 

.22 o* 


*n 





<D o 

<D o*' v 

S°o 


CD 

O) 

O o 

2§ 

<D 2k 

^ S 

CJ (M 5 O 

« o 

■p Cu 

J o 

* s 


»—5 ^ 

4-» 

,c 

rr IM 

W 

^ 

o 



CO 


V-O 

X 


CO 

C2 


// 

// 

// 

u 

u 

// 

// 

// 

// 

12 

27.5 

18.5 

13 

9.5 

11 

11 

14.5 

16 

11.5 

13 

30 

18 

12 

9.5 

11 

11 

14 

16 

11 

14 

31 

18.5 

12 

9 

11 

11 

14 

16 

12 

15 

29 

18 

12 

9 

10 

11 

13 

16 

12 

16 

29 

18.5 

12 

9 

10 

11 

13 

16 

12 

17 

25 

18 

11 

8.5 

10 

10.5 

12 

15 

12 

18 

21 

18 

10 

8 

10 

10.5 

12 

15 

12 

19 

206. 

17.5 

106 

8 

10 

10 

12 

15 

11 

20 

20 

17.5 

10 

8 

10 

10 

11 

14.5 

11 

21 

20 

176 

10 

8.5 

10 

10 

10 

14.5 

11 

22 

20 

17 

10 

8 

■ 9.5 

10 

10 

13 

10 

23 

19 

17 

10 

8 

9.5 

10 

9.5 

12 

10 

24 

19 

17 

10 

7.5 

9.5 

10 

9.5 

12 

10.5 

25 

21 

17 

8.5 

7 

10 

10 

9.5 

11 

10 

26 

21 

16.5 

8.5 

7 

9.5 

10 

9.5 

10.5 

9 

27 

22 

16.5 

8 

7 

9.5 

9.5 

9 

10 

8.5 

28 

20 

17 

8 

7 

8 

9.5 

9 

10 

9 

29 

23 

16.5 

8 

6.5 m 

. 8- 

9 

8.56 

10 

9 

30 

17 

16.5 

8 

76 

8 

96 

8 

9 

8.5 

31 

20 

16 

7 

8 

76 

9 

7.5 

9 

8.5 

32 

18 

16 

7 

8 

6 m 

8.5 

7 

9 

8.5 

33 

18 

16 

7 

8 

6 

8 

7 

8.5 

8 

34 

17 

16.5 

7 

7.5 

8 

8 

6.5 

8.5 

8 

35 

17 

16.5 

7 

’ 7.5 

7 

8 

7 

8 

8 

36 

16.5 

16 

6.5 

8 

7 

8 

8 

8 

8 

37 

16 

16 

7 

7.5 

7 

8 

7 

7 

8 

38 

15 

15 

6.5 

7 

7 

8.5 

7 

76 

8 

39 

15 

14 

7 

8‘ 

7 

8.5 

7 

7 

7 

40 

15 

14 

6.5 

7.5 

8 

7 

6.5 

7 

7 

41 

14.5 

14 

7 

7.5 

8 

7 

6.5 

. 7 

7 

42- 

18 

14 

6m 

7.5 

7 

7 

6 

7 

6.56 

43 

16.5 

14 

7 

7.5 

7 

7 

6 

6.5 

7 • 

44 

15 

14 

7 

8 

7 

7 

6 

6.5 

7 

45 

16 

14 

7 

7.5 

8 

7 

6 

6 

7 

46 

15 

14.5 

6.5 

7.5 

8 

6.5 

6.5 

6 

6.5 

47 

15 

14.5 

7 

8 

8 

6 m 

6.5 

6 

6.5 

48 

15 

14 

6.5 

8 

9 

6.5 

6.5 

6 

6.5 

49 

13 m 

14 

' 7 

8.5 

9 

7 

6 

6 

6.5 

50 

13 

13m 

7 

9 

9 

7 

6 

5.5 

6.5 

51 

13 

13* 

6.5 

9 

9 

7 

6 

5.5 

6.5 























































26 


Experimental Inquiries respecting Heat and Vapor.. 


TABLE CONTINUED. 


Older of succession in the ex¬ 
periments of each se;ies. 

•*> *-» 

ci O 

r\ —** . 

£ y 9 

« s-'i: 

4Ji 

» G r 

CC 5* w 
aj v *- 

— «3 *■ 

x o 

S co 2 

2d series, 1-8 oz. of water, at 
80°. Iron very blight red. 

3d series, 1-4 oz. of water, at 
212°.. lion near whiteness. 

• i 

4th series, 1-Soz. of water, at 

11)9°. lion blight red. 

5th series, 1-8 oz. of water, at 

190°. iron bright red. 

6th series, 1-8 oz. of water, at 

200°. Iron near whiteness 

7th series, 1-8 oz. of water, at 

200°. Iron nearly white. 

_ 

8th seiies, i-lboz. ot water, 

at 212°, kept in rapid ebul¬ 

lition during the whole se¬ 
ries. Iron white. 

9th series, 1-lGoz. of w r ater, at 

212°, kept briskly boiling. 

Iron white. 


// 

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4 


Experimental Inquiries respecting Heat and Vapor. 27 


TABLE CONTINUED. 


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28 


Experimental Inquiries respecting Heat and Hapor 


TABLE CONTINUED. 


Order of succession in the ex¬ 
periments of each series. 

1st series, 1-8 oz. of water, at 
65° at each exp. Iron red hot 
when taken from the fire. 

2d series, 1-8 oz. of water, at 
80°. Iron very bright red. 

3d series, 1-4 oz. of water, at 

212°. li on near whiteness. 

133 

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Experimental Inquiries respecting Heat and Vapor. 


29 


RESULTS. 

1st Series .—Vaporized oz. of water in 2100"—viz. 

water was on the metal 1497" ) 

59 intervals 10.2" each 603" \ 

Black at No. 19.—Minimum, No. 49. 

2d Series .—Gave 6 ¥ 2 oz. of vapor in 1800"—viz. 

water remained on 1292.5" ) 

61 intervals 8.32" each 507.5" \ 

Black at No. 21.—Minimum, No. 50. 

3d Series .—Gave 6 ¥ 3 oz. of vapor in 1800"—viz. 
water was on 1065.5" ) 

67 intervals 10.9" each 734.5" \ 

Black at No. 19.—Minimum, No. 42. 

4th Series .—Gave 7 ¥ 3 oz. of vapor in 1920"—viz. 
water was on 1092" > 

72 intervals 11.5" each 828" ^ 

Black at No. 30.—Minimum, No. 29. (Surface oxidized.) 

5th Series. —Gave oz. of vapor in 2100"—viz. 

water was on 1244.5" ) 

79 intervals 10.8" each 855.5" \ 

Black at No. 31.—Minimum, No. 32. (Oxide.) 

6th Series .—Gave 9 g 2 oz. of vapor in 2100"—viz. 
water was on 1420" ) 

91 intervals 7.47" each 680"$ 

Black at No. 30.—Minimum, No. 47. 

7th Series .—y oz. of vapor in 2162"—viz. 

water was on 1232" ) 

93 intervals 10" each 930" ) 

Black at No. 29.—Minimum, No. 52. 

8th Series .—Gave Ye 3 oz * °f va P or hi 2700"—viz. 
water was on 1819" ) 

162 intervals 5.44" each 881" $ 

Black at No. 38.—Minimum No. 52. 

9th Series .—Gave y/ oz. of vapor in 2700"—viz. 
water was on 1510" ) 

172 intervals 6.91" each 1190" ^ 

Black at No. 42.—Minimum, No. 75. 

The eighth series in the second course, is represented in projec¬ 
tion by the curve, (Fig. 4.) of the accompanying plate. The reader 
will remark that the linear unit, assumed to represent the minimum 
time and its corresponding quantity of vapor, is one tenth of an inch 
in this figure, whereas it is two tenths in those which relate to the 
first course. 

In addition to the results of the fourth and fifth series, where the 
most rapid action occurred almost simultaneously with the cessation 


80 Experimental Inquiries respecting Heat and Vapor. 

of redness, numerous other facts had convinced me that the approach 
to this period is greatly accelerated by the adhesion of any non-con¬ 
ducting substance to the surface of the iron. Indeed, it often appear¬ 
ed sufficient for the water to find and seize upon a mere point of such 
material as a nucleus, to enable the fluid speedily to reduce the tem¬ 
perature of the surrounding surface. By detaching a scale of oxide, 
around which the effect just described had begun to take place, I have 
sometimes succeeded in arresting the progress of vaporization, and 
by giving the liquid once more a clean red surface, even with the 
scale floating loosely in the water, to establish once more the slow 
evaporation which belongs to that state of the metal. 

To ascertain what effect the incrustation generally formed upon 
the interior of a steam boiler might bte expected to produce, in aug¬ 
menting the rapidity of action in a case of overheating, I performed 
the following course of nine series, employing for that purpose, the 
basin used in the first course, commencing with its surface clean, and 
having tried the effect of pure water at 212°, subsequently poured 
in a portion of cold water, into a pint of which about two ounces of 
clayey garden earth had been put, producing a degree of turbidness 
as great probably as any of our rivers possess in the time of freshets. 
The iron was kept constantly over a brisk fire, and, in some of the 
series, was permitted to come to bright redness before each experi¬ 
ment; while in others, the operation commenced with redness, but 
was continued in so immediate a succession, as to reduce the metal 
to a certain point of constant action ; but never attaining the most 
rapid period. 

It will be perceived that the first series was made in pairs, alter¬ 
nately—two with clean water at the boiling point and two with the mud¬ 
dy water above mentioned. The other series were made with similar 
alternations of single experiments, with the exception that both hot 
and cold water were free from impurities when laid upon the metal. 
The ratios placed among the results of this course, will prove that 
on an average, water at 212° laid upon hot metal under the circum¬ 
stances described, requires 15J per cent, longer for its evaporation 
than a like quantity of water at 60°. This result, which appears at 
first rather startling and paradoxical, is readily explained when we 
consider the efficacy of cold water in bringing the coating and even 
the surface oi the metal down towards the temperature of most rapid 
action,—a point, at which the mere difference of temperature be¬ 
comes an insignificant element in the calculation, compared with the 
vastly augmented speed with which the vapor is then generated. 


Experimental Inquiries respecting Heat and Vapor 


31 


Third course, embracing nine series. 

To exhibit the effect of incrustations in augmenting the action of 
hot metal, during the first stages of vaporization from its surface, 
and also to show the relative efficacy of hot and cold water in this 
particular. 


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Order of experiments in each se 

1st Series.- 
at each < 
with cla] 

2d Series.- 

3d Series.- 
water, f( 
1-8 oz. e 

4th Scries. 

5 th Series. 
at brighl 
of consta 

6 th Series. 

7th Series. 
ter to the 
45"—1-1 

8th Series , 
35'—th« 
applied- 

9th Series .—On the coat of cla; 

clean water at 6t 

Water, 212° (clean.) 

Do. 60° (muddy.) 

Do. 212° (clean.) 

Do. 60° (muddy.) | 

Do. 212° (clean.) 

Do. 60° do. 

Do. 212° do. 

Do. 60° do. 

Do. 212° do. 

Do. 60° do. 

Do. 212° do. 

Do. 60° do. 

Ido. 212° do. 

1 

Do. 60° do. 

Do. 212° do. 

Do. 60° do. 


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32 


Experimental Inquiries respecting Heat and Vapor. 


RESULTS. 

1st series. —Time reduced from 100' 'to 18" by the coat of earthy mat¬ 
ter successively deposited from f ths oz. of muddy water. 

W 

2d series. —Hot water constant at 13.5" 

Cold water do. do. 

3d series. —Mean time for hot water 15.6"—coated metal red hot, 

each time. 

Mean time for cold water 13.37". 

Ratio of cold to hot 1 : 1.167. 

4th series. —Hot water constant at 12". 

* 

Cold water constant at 10.5". 

Ratio of cold to hot 1 : 1.143. 

5th series. —Hot water constant at 13". 

Cold water constant at 11.5". 

Ratio of cold to hot 1 : 1.130. 

\ 

6th series. —Mean time for hot water 32.6". 

Mean for cold water 26.2". 

Ratio of cold to hot 1 : 1.244. 

7th series. —Mean for hot water 23.6". 

Mean for cold water 20.6". 

Ratio of cold to hot 1 : 1.145. 

V 

8th series. —Mean for hot water 16.5". 

Mean for cold water 15". 

Ratio of cold to hot 1 : 1.100. 

9th series. —Constant at 25" to the ounce. 

The first series represents the gradual diminution of time from 
100 “ down to 18” and shows that here the impurity suspended in 
the water, retarded vaporization more than the depression of tem¬ 
perature could accelerate it. In the second series, the two effects be¬ 
came exactly counter-balanced and so remained through several ex¬ 
periments more than are given in the table. 

Fourth course, consisting of six series. 

The sixth being intended to show the times required to evaporate, 
or to vaporize equal portions of water from the surface of iron when 
placed cold upon a vivid coal fire, with the delays necessary to raise 
the temperature up to the point of most rapid action and thence to 
the state in which the water ceases to moisten the surface ;—the oth¬ 
er series being designed to exhibit the relation in time, between hot 


Experimental Inquiries respecting Heat and Vapor. 33 

and cold water upon a clean surface, varying the correspondent por¬ 
tions of each from Joz. to 2oz. at each experiment. 


Order of experiments. 

1st Series. —1-8 oz. at 
each experiment— 
hot and cold water 
alternately. 

2d Series. —1-4 oz. at 
each experiment— 
hot and cold watei 
alternately. 

3d. Series. —1-2 oz. at 
each experiment— 

hot and cold water 
alternately. 

4th Series. — 1 oz at 

each experiment— 

hot and cold water 

alternately. 

1 

5th Series. —2 oz. at 

each experiment— 

hot and cold water 

alternately. 

6th Series. —1-8 oz. 

put on the iron cold, 

and same quantity 

in immediate suc¬ 

cession. 

o" 

<N 

<N 

s 

£ 

o* 

o 

CO 

6 

Q 

Water 212°. 

— 

o 

o 

CO 

6 

Q 

O* 

rH 

s 
•*—» 
a 

£ 

o 

CO 

6 

P 

Water 212°. 

o 

o 

CO 

6 

P 

Water 212°. 

o 

o 

CO 

o 

P 

1 

Water 60°. 


// 

// 

// 

n 

a 

ii 

ii 

II 

ii 

II 

ii 

1 

104 


108 


150 


182 


266 


40 

2 


68 


93 


137 


158 


220 

16 

3 

96 


102 


150 






9 

4 


64 


84 


126 





ceased 60" 9 

5 

100 










8 

6 


94 









ceased SO" 8 

7 

90 










6.5 

8 


79 









6 

9 

95 










ceased 60" 6 

10 


74 









black 64 

11 

90 










visibly red 60 

12 


80 









75 

13 

80 










clear red 73 

14 


74 









“ 80 

Mean. 

93.5 

76 

105 

88.5 

150 

131.5 

182 

158 

226 

220 

constant 80" 

Ratio. 

1.23 

: 1 

1.186 : 1 

1.14 : 1 

1.151 

: 1 

1.209 : 1 



The mean of all these ratios is 1.183 which shows that with a 
clean surface the limited quantity of hot water requires 18 r \ per 
cent, longer to effect its vaporization from the red hot metal than an 
equal quantity of water at 60° ; so that though the times are vastly 
different in this course from what were given in the last, the relation 
is nearly the same, being only 3 per cent, more favorable to the cold 
water, than when the surface was incrusted with earthy matter. Ac¬ 
cidental circumstances sometimes vary or even invert the relative 
times for hot and cold water, but such discrepancies are easily refer¬ 
red to their proper causes. The limits of this paper compel the 
postponement of several courses of experiments. 
















































. 

- 




- 

. • 






■ 


. 




' • <1 " • ‘ 

































































































































































































EXPERIMENTAL INQUIRIES, &c. 


Tiie developement of the law of action between a heated surface 
and water of different temperatures, has been, in part, presented by 
preceding courses of experiments. 

To persons conversant with this subject it will readily occur, that 
the facts and principles connected with vaporization are highly im¬ 
portant to the arts, independently of their relation to the steam en¬ 
gine. The numerous processes of manufactures, in which liquids 
are to be reduced by boiling, are often performed in a manner totally 
at variance with philosophy, as well as with economy. The manu¬ 
facture of salt by vaporization, for example, is an extensive and in¬ 
creasing branch of our national industry, and is generally carried on 
with very little attention to the saving of fuel, by any of those devices 
and arrangements which the practical science of the present age 
might suggest. 

The chief points proposed to be examined at present, are— 

1. The temperature of most rapid vaporization under atmospheric 
pressure. 

2. The nature of the phenomena exhibited at that point, as well 
as immediately above and below it. 

3. Effects of lubricating the surface of the metal, of covering the 
surface of the water with a thin fibrous texture, and of thickening it 
with a farinaceous substance. 

4. The influence of mechanical pressure in bringing the liquid in 
contact with the metal and accelerating the vaporization. 

5. The action of hot metal on other liquids, particularly alcohol. 

6. Some opinions which have gained currency in regard to the 
temperature of repulsion, and the degree of rapidity with which heat 
may be imparted to liquids, will likewise require attention. 

1. To ascertain the temperature at which the most rapid action 
takes place, two methods have been employed. The first was by 
using a basin of wrought iron, having at the bottom a small quantity 
of mercury, into which the bulb of a thermometer was plunged. 
Upon the surface of the iron, near the mercury, small measured por¬ 
tions of water were successively deposited, while the basin was pla¬ 
ced over an argand spirit lamp. These portions were not of suffi¬ 
cient amount or frequency to prevent the increase of temperature in 

6 



1 


36 Experimental Inquiries respecting Heat and Vapor. 

the metal, and consequently the times of vaporization were diminish¬ 
ed to a certain point, after which they were observed to increase. 
The temperature had then reached the point where repulsion begins. 
The temperature at the moment when the point of repulsion appear¬ 
ed to have been attained was noted, and the experiments continued 
until an unequivocal increase in the time of evaporating the unit of 
water was observed. The lamp being now withdrawn, the tempera¬ 
ture was allowed to descend, and the rapidity of vaporization was of 
course augmented ; still lowering the temperature, the point of great¬ 
est action was passed, and the production of steam became slower 
from want of sufficient heat. 

By thus reversing the temperatures, and alternately passing and 
repassing the point of most vigorous action, the limits of that action 
were determined to a certain degree of exactness. It soon became 
evident, that it was far below the boiling point of mercury, and con¬ 
siderably above that of water boiling in open air. It was not diffi¬ 
cult to ascertain too, that the range of most rapid action lay between 
300° and 350°. In order to vary the mode of experimenting, and, 
at the same time, to give more exact indications in several particu¬ 
lars, the second method, above referred to, was devised. This con¬ 
sisted in employing a bar of iron, about 14 inches long, 1 T \ wide, 
and 1 T \ thick. A number of cylindrical holes, half an inch in diam¬ 
eter, and one inch apart, (from centre to centre,) were bored along 
one of the sides, extending nearly through the thickness of the bar. 
Adjacent to each of these holes, which were five in number, were 
sunk small conical cavities, T \ of an inch deep and T 7 ^ of an inch in 
diameter at top, forming basins or cups to receive drops or other 
small measured portions of liquids. The cylindrical holes were to 
receive mercury, into which the bulbs of thermometers could be 
plunged, to ascertain the temperature of the part of the bar and of 
the cup opposite. The thermometers were supported from above, 
by hooks bent over the bar and placed in proper positions to allow 
the bulbs to descend just far enough to be completely immersed in 
the reservoir of mercury, but not to carry the centre of the bulb 
below the level of the bottom of the contiguous cup. 

By this means the temperature of the mercury was measured, at 
a point where it must have been the same as that of the generating 
surface. The five receptacles of mercury were placed near the 
middle part of the bar, leaving a part four and a half or five inches 
long at each end, without holes; but the line of cups already men¬ 
tioned was extended in both directions, nearly to the extremities of 


37 


Experimental Inquiries respecting Heat and Vapor . 

the bar. By this means the nature and mode of action could be 
observed, at points above that of mercurial ebullition. 

Heat was applied at one end of the bar, either by means of a 
spirit lamp, or by thrusting the end into an opening through the side 
of a furnace. As the temperature rose, the cups near the end next 
the fire, were, of course, first brought to a vaporizing temperature; 
then the cup opposite to the nearest mercurial reservoir and the 
others in succession, with greater or.less rapidity according to the 
tension of the heat at its source. It was generally found most ad¬ 
vantageous to employ, for a source of heat, the convenient chemical 
spirit lamp with argand burner, which has been devised by Dr. J. K. 
Mitchell. When the temperature was sufficiently raised, drops of 
water were simultaneously projected into two or more of the cups, 
and by the inequality in the times of final disappearance, their rela¬ 
tive influence was easily perceptible. This mode of operating, by 
allowing the temperature to be gradually raised admitted of a suc¬ 
cession of five series of trials, one for each cup, so that when the 
time of vaporization, in one, had begun to increase , that is, when the 
time of most rapid action in that cup had been passed, and the action 
had become slow through excess of heat, it was only necessary to 
commence with the next cup, more remote from the source of heat. 
The period of greatest rapidity was now perceived to lie between 
304° and 320°. The range of temperature through which the most 
rapid action existed was hence limited between two points, equally 
remote from 312°, or from 100° above the boiling point of water. 

2. The nature of the effect here observed resembled that of vig¬ 
orous attraction. This necessarily creates a constant struggle be¬ 
tween the vapor which is quitting, and the liquid which is approach¬ 
ing any given point of the metallic surface. On brass, the action 
appeared more vigorous, and the temperature of repulsion higher 
than in the case of iron. On mercury, at 500°, a drop of water 
was, on one occasion, found to remain seventy seconds; but at 340° 
a drop of this metal formed a good nucleus, about which the water 
when repelled by a surface of iron, at the same temperature, would 
gather, and thence obtain heat to vaporize itself, while portions not 
in contact with the mercury would lie upon the iron almost quiescent. 

At temperatures considerably below that of most rapid vapori¬ 
zation, there was constantly exhibited, in the various series of experi¬ 
ments, a decided tendency in the water to adhere to the metallic 
surface, and when by contact with a given portion of surface, and by 
receiving and rendering latent in vapor, the heat which the latter had 


38 


Experimental Inquiries respecting Heat and Vapor. 

possessed, the. temperature of that portion was somewhat reduced, 
the stratum of water was observed to glide away to other, hotter 
parts of the surface, even against the force of gravity. 

This effect was observable in the cylinders with'which the second 
course on variable rapidity , was performed. Towards the conclu¬ 
sion of each series, the water, after ceasing to boil in the bottom ol 
the cylindrical cavity, ascended in many instances quite to the top of 
the cylinder, and even spread outward on all sides wherever it met 
with a higher temperature than 212°. 

The same phenomenon was noticed in the basin already described,, 
and in the bar above mentioned. To make this effect the more dis¬ 
tinct, a broad shallow pan of extremely thin iron, commonly called 
by the tin plate workers, “ black tin,” was procured. In the centre 
of this, a slight elevation, about one tenth of an inch high, was made, 
with a corresponding cavity on the under side, or bottom of the pan. 

A lamp being applied beneath the elevated part, the iron soon ob¬ 
tained a dull red heat in the dark. Water was then laid upon the 
basin so as to surround completely the centre, and form a sort of 
island of heated surface.' As the heat extended by degrees, and 
reached the line of water, the latter was observed to start upwards 
from its line, and moisten a portion of the surface not before wetted. 

By agitating the water with a hair pencil, and creating a w r ave 
towards the centre, the line of vaporization became distinct. By 
raising the waves still higher, that of repulsion was manifest, and by 
causing a surge high enough to break quite over the insulated eleva¬ 
tion, the alternate attractions and repulsions were seen in the drops 
and masses which, having been driven forcibly beyond the first line 
of vaporization, or that which they encountered on their ascent, were 
subsequently rolled quite over the centre of the elevated embossment, 
but arrested with great promptitude as they rolled down and reached 
the line of vaporization on the opposite side. 

3. In order to ascertain the influence of certain lubrications in re¬ 
ducing the rapidity, I placed the bar over a spirit lamp in such a 
manner as to bring two of the mercurial reservoirs, and their adjacent 
cups at equal distances from the centre of flame. Having allowed 
the temperature to reach 300°, I applied equal portions of water to 
each cup, and found their actions precisely alike. 1 then placed and 
spread, as lightly as possible, a minute portion of olive oil, forming 
a thin film over the surface of one of the cups, allowing the other to 
remain clean. On renewing the applications of water, it was found 
that the oiled took four times as long as the clean surface to vaporize 


30 


Experimental Inquiries respecting Heat and Vapor. 

a certain quantity of water. On elevating the temperature, the oil 
itself was gradually evaporated, and the water found occasional ad¬ 
mittance to the surface. Hence the difference was gradually dimin¬ 
ished, and the wonted action of the iron restored, but the addition 
of fresh portions of oil, again reduced temporarily the vaporization 
on the surface to which it was applied. But as the temperature was 
more elevated than before, the oil likewise became sooner dissipated. 

By exposing the bar in a similar manner, and ascertaining that 
two contiguous cups, equally remote from the centre of flame, were, 
when both clean, precisely alike in regard to the rapidity of evapo¬ 
ration at a high temperature, I lubricated one with plumbago, laid on 
by rubbing a piece of that substance over the interior, without how¬ 
ever leaving any dust or small bits of the mineral to serve as nuclei 
for the water to seize upon. The other cup was left clean as before. 
Equal portions of water at 60° were now laid simultaneously upon 
the bottom of the two cups. The mean result, of six experiments 
in each, was that the cup with plumbago required eighty four seconds 
to evaporate its liquid, while the cup without plumbago took but forty 
one for that purpose. The portions of liquid used were single drops 
for the respective experiments. 

To ascertain the effect of thickening the water into a thin paste, I 
put a large tea-spoon full of flour into an ounce of water, and laid 
one-fourth of an ounce of the mixture on the bottom of the iron ba¬ 
sin, kept red hot over the fire. The evaporation took place, and 
the paste became dry in seventy-eight seconds. Under precisely the 
same circumstances, clear water, of the same temperature as that 
mixed with the flour, required one hundred and thirty-eight seconds 
to evaporate one-fourth of an ounce. 

The action on clear water was rendered much more rapid, howev¬ 
er, by covering the surface with a circle of white paper laid on imme¬ 
diately after the water was put into the basin. The evaporation then 
took place in seventy-two seconds. In another experiment, in which 
the circle of paper was smaller than that of water, the time was in¬ 
creased to ninety seconds. In both of these cases, the acceleration 
appeared to proceed, in part, from the obstruction which the paper 
opposed to the rotation of the circle of water. When a very small 
circle of paper, or any other light body, was placed upon the surface, 
it soon acquired the motion of the fluid, and the exceeding velocity 
of the latter became manifest to the eye. The rotary motion is not 
however the uniform result of such experiments. 


40 


Experimental Inquiries respecting Heat and Hapot. 

There will often be seen a scalloped figure with a greater or less 
number of re-entering curves, destroyed and reproduced with aston¬ 
ishing rapidity and regularity. A slight humming noise was also oc¬ 
casionally perceived, as the liquid was alternately raised and depress¬ 
ed by this species of movement. Gravity was here put in equilibrium 
with the repulsive force of caloric, and as the equilibrium must from 
the nature of the fluid be unstable , there was a constant effort of those 
parts of the fluid which happened for a time to be less resisted than 
others by the heat, to obey gravity and come nearer the surface ; but 
as they descended they came to be, in turn, more vigorously resisted, 
and sent up again with energy, even beyond the distance of equilibri¬ 
um. A new descent was the consequence, and the alternation once 
established, was easily maintained by the momentum of the fluid and 
the perfect elasticity of the spring on which it constantly impinged. 
This phenomenon is similar in character, and probably admits a sim¬ 
ilar explanation to that of an experiment of Mr. Faraday, in which a 
segment of a cylinder of metal has a narrow groove cut longitudinal¬ 
ly along the convex side, forming two straight edges one or two 
tenths of an inch asunder. If this segment, heated to four or five 
hundred degrees, is laid on another polished metallic plane surface, 
so as to rest upon the two edges, it will soon acquire a rapid oscilla¬ 
tory motion, bringing the two edges alternately in contact with the 
plane below. This oscillation may be sufficiently rapid to cause a 
ringing or humming noise. In this case the radiation is from the os¬ 
cillating body doivnwards , while in that of a fluid undergoing evapo¬ 
ration, it is from the fixed plane to the oscillating body or liquid up¬ 
wards. 

The temperature of the liquid while resting over the red hot sur¬ 
face of iron, was found to be 210°. 

4. The resistance to actual contact, which is furnished by heat in both 
the cases just mentioned, is exemplified in many processes of art. 
The attempt to perforate a bar of hot iron with a cold steel bit , will 
present a sensible illustration of this point. The resistance may how¬ 
ever, by mechanical pressure, be overcome to such an extent as to 
bring the solid in one case, and the liquid in the other, into such con¬ 
tiguity, as to restore in some degree the adhesion of the liquid or the 
abrading power of the steel. The pressure may be applied directly 
to the liquid when placed upon a metallic plate, by means of another 
smooth metallic surface pressed immediately upon the drop of liquid. 
Smart vigorous explosions may be thus produced, similar to the well 
known cracking under a smith’s hammer which has been dipped in 


41 


Experimental Inquiries respecting Heat and Fapor. 

water and then applied to a hot bar of iron, or to the overheated face 
of an anvil. 

The pressure of an elastic gas or vapor may, in like manner, be 
employed to urge the liquid into contact with the metal; and, it is ev¬ 
ident, must become at every instant the more effectual, both as the 
pressure is increased by the accumulating mass of steam, and as the 
temperature is diminished towards the point of most rapid action. It 
will be understood that the calculation formerly made respecting the 
power which an overheated boiler of given dimensions could pro¬ 
duce, was intended only to exhibit the amount of atmospheric steam. 

5. It becomes interesting to inquire whether any other liquid than 
water is affected, in a similar manner, by the overheated metallic sur¬ 
face. The trial soon convinced me that in regard to alcohol, at least, 
the same general phenomena take place. It may at first appear sin¬ 
gular, that a given portion of this liquid, (the boiling point of which 
is at 174° Fahr.) should require for its evaporation a longer time 
when laid upon a plate of iron at 400° or 500° than when poured 
into the hand of the experimenter, the temperature of which is not 
above 98°. Such however appears to be the fact. When one six¬ 
teenth of an ounce of alcohol was laid upon the centre of an iron 
basin, heated to at least 500°, the time of its final disappearance 
was one hundred and forty five seconds; while an equal quantity of 
the same spirit required but ninety seconds to evaporate it from the 
palm of the hand. It is true, that in the latter case, the extent of 
surface occupied by the spirit was unavoidably greater than that on 
the iron. The liquid was diffused by capillary attraction, or perhaps 
by its attraction for heat, over the whole surface of the palm, not¬ 
withstanding the efforts to confine it to a single spot. At a tempera¬ 
ture when the iron became barely red in the dark, the lime of dis¬ 
appearance was from one hundred and ten to one hundred and 
twenty seconds. 

The next thing was to determine the time requisite to vaporize one 
sixteenth of an ounce of alcohol, when the metal was at a temperature 
to give a maximum energy of action between it and the spirit. By 
several trials for this purpose, it was found to be three and a half 
seconds. The greatest length of time during which the same quan¬ 
tity had been found to remain was one hundred and fifty seconds. 
Whence it appears, that the relation between the two is 77^=3 J T , 
or nearly. The only remaining question was the actual temper¬ 
ature at which the spirit disappeared in the least time. For this pur- 


42 Experimental Inquiries respecting Heat and Hapor. 

pose, recourse was had to the bar with mercurial reservoirs and cups, 
already described. On raising the temperature to 312°, where wa¬ 
ter had been observed to be most rapidly vaporized, it was manifest 
that the alcohol was clearly and strongly repelled. 

The temperature was then lowered to 280°, when occasional signs 
of adhesion were manifested, and a corresponding diminution in the 
time of evaporating a given quantity'of liquid was the result. 

By lowering the temperature of the iron to 260°, the time was 
again perceived to increase on account of a deficiency of heat. By 
thus passing and repassing several times between 260° and 280°, 
the limits of range became circumscribed between 270° and 278°, 
and finally the point of most vigorous action seemed to rest at 274°, 
the arithmetical mean of the above mentioned limits. This, it will 
be recollected, is 100° above the boiling point of alcohol. It will 
be observed also, that this is exactly as much above its boiling point, 
as the temperature of most activity on water is above the boiling point 
of that liquid. 

6. An allusion has alread-y been made to the opinion of some writers, 
that the repulsion of a liquid from metal begins at the temperature of 
incandescence, and increases as the temperature rises. The facts 
already detailed in this paper, will serve to show that the former opin¬ 
ion is wholly without foundation. Indeed, when we reflect for a mo¬ 
ment on the nature and cause of that diminution of the liquid which 
takes place after vaporization has ceased through an excess of tem¬ 
perature , we must perceive that as the effect is an evaporation , due 
to the radiation of heat, the rapidity with which the latter will dis¬ 
perse a given quantity of water must be proportionate to the tension 
of the heat at the radiating source; that is, the surface of the metal. 
Evaporation must commence where vaporization ceases, and the 
former must be slow when the tension is barely sufficient to elevate 
the liquid out of the sphere of contact, or of contiguous attraction. 
This cannot however prevent an increase of rapidity, when the ten¬ 
sion at the source is sufficiently elevated to allow the radiated heat to 
communicate temperature to a transparent medium. 

To place the matter beyond a doubt, the iron basin already men¬ 
tioned was used. When exposed to the white heat of a forge fire, 
a given weight (one eighth of an ounce) of water was evaporated in 
sixty seconds. At the bright red heat of an anthracite stove, eighty 
seconds were required to produce the same effect. When exposed 
on an open grate of anthracite, in such a manner as to maintain the 


43 


Experimental Inquiries respecting Heat and Vapor. 

centre only of the basin at a very faint red heat in the dark, the time 
was extended to three hundred and fifteen seconds. 

Another comparison, made upon portions of water of one sixteenth 
of an ounce each, gave the following results. On the metal, at the 
bright red heat of the stove, the water lay sixty six seconds; on the 
centre of the basin dull red, as before, in the dark, it continued one 
hundred and eighty three seconds; while over a spirit lamp, the metal 
being constantly black and the temperature probably not above 600°, 
it remained two hundred and eighty six seconds. 

In all the above experiments, the heat was constantly supplied, and 
the temperature may be regarded as having been uniform during each 
trial. Hence, the opinion that repulsion increases with the tempera¬ 
ture, appears not to be sustained. When the temperature has deci¬ 
dedly surpassed the point where contiguous attraction can take place, 
every elevation of temperature is attended with a corresponding dimi¬ 
nution of time required for evaporation. 

In order to illustrate more fully this branch of the subject, a series 
of experiments was made with the iron basin, placed over a coal fire 
and supplied with doses of one sixteenth of an ounce of alcohol, sp. 
gr. .854, (32.5° Baume.) The first experiment was made at a 
temperature about 400° to 500°. 

The following was the succession. 

Exp. 1 142" Exp. 3 140'' 

2 - - - 145 4 - - - 117 

The temperature of the metal continued to rise notwithstanding the 
application of the successive portions of spirit, and as the time for 
each experiment was obviously decreasing through an excess of tem¬ 
perature , the basin was removed from the fire and allowed to stand 
for some time, until it was cooled below the point of minimum activity . 
Tt was then again placed upon the fire, and when the fifth portion of 
liquid was placed upon it, exhibited symptoms of a slight tendency 
to attract the latter. The sixth experiment was made after sufficient 
time had elapsed again to permit a rise of temperature. 


Exp. 5 

87" < 

[ Rapidity increased by deficiency of tempera- 

[ ture to maintain the repulsion uninterrupted. 

c\ 

150 

\ Iron kept some time on the fire without liquid 

o 

\ before this experiment. 

7 

143 


8 

134 


9 

123 



7 


/ 






44 Experimental Inquiries respecting Heat and Vapor. 


xp. 10 

120 " 

11 

115 'l 

13 

113 | 

14 

100 

15 

95 

16 

82 




The surface of the basin about the spirits exhibited when the room 
was darkened, a very distinct luminousness, like a faint lambent 
flame, owing, probably, to the vapor being heated nearly to redness 
at the moment of production. A similar appearance had been ob¬ 
served in the vapor of water, produced from metal at a white heat. 

Having now removed the basin from the fire, the experiments 
were continued, and the time was observed to increase from eighty 
two seconds to one hundred and five, and then to one hundred and 
thirty five, after which it began to diminish, as the establishment of 
cohesion between the liquid and the metal became more decided, thus 
Exp. 17 - - 105" Exp. 20 - - 17" 


18 - - - 135 21 10 

19 90 


The above series of experiments is in accordance with several of 
those made upon water, where the initial temperature of the iron was 
very great and the mass sufficient to supply heat of a high tension, 
to the evaporating surface, for a considerable length of time after 
being removed from the fire. This was the case in the first, second , 
fifth and eighth series in the second course on the rate of decrease.* 

In those cases, the times exhibited either a succession of numbers 
nearly equal, or an actual increase during the first five or six experi¬ 
ments of each series. This is particularly remarkable in the eighth 
series, of which a projection has been given. The order of magni¬ 
tudes, for the first six experiments, beginning with the highest, was 
followed in that projection, merely for the purpose of exhibiting the 
extremes of retardation, both by excess and by deficiency of tem¬ 
perature, in the production of vapor. The reader will perceive 
however that the actual order of occurrence of these six experiments 
which began at a white heat and lasted, including intervals, 218.7 
seconds, was 27.5, 28, 44, 39, 30, 33. It needs hardly be stated, 
that the idea of instantaneous action between iron and water, derives * 
no confirmation from any of the foregoing series of experiments. 


44 See page 24. 





Experimental Inquiries respecting Ileat and Vapor. 


45 


Description of an instrument called the Steam Pyrometer. 

A carelul attention to guard the containing vessel in which we 
produce steam from boiling water by means of metal, or other solid 
or liquid bodies capable ol being heated in open vessels above 
212 ° Fah. will enable us to measure with great accuracy, the quanti¬ 
ty of heat which such solid or liquid body expends iu cooling, from 
the temperature at which it is first put in, down to the boiling point 
of water. 

The mode of calculating the temperature when the specific heat 
is known, has already been given. The only points of much diffi¬ 
culty in rendering the formula heretofore stated, directly useful in 
pyrometry are, 1, the necessity of defending the vessel in which the 
steam is produced, from the effects of radiation and conduction dur¬ 
ing the operation; 2, the obviating of loss in transferring the hot 
body to the liquid through the air; 3, the means of obtaining and 
marking the true boiling point, and 4, the means of speedily and ac¬ 
curately weighing the liquid, and showing how much has been evapo¬ 
rated during an experiment. 

To these causes of inconvenience, may be added, that which results 
from the low specific heats of some of the substances, to be employ¬ 
ed as standards.—Such are several of the metals as platina, gold, 
&c. It is obvious that the method of plunging the body of which we 
would know the temperature direcdy into boiling water, can be 
adopted only with regard to solids, which remain unchanged after 
being quenched in water, and which are not capable of imbibing the 
fluid, on account of porousness, or such physical characters as would 
render them liable to combine chemically with the water. 

When we have to deal with liquids of which the temperatures extend 
beyond that of boiling mercury, that is, of mercury boiling in vacuo, 
(which must necessarily limit our use of the mercurial thermometer,) 
we must either pour such liquid into the boiling water, if a melted metal 
which will not undergo change in that method of cooling, or must en¬ 
close it in a suitable vessel extremely thin and of materials to sustain the 
action of water upon it, or must immerse in the hot liquid or the melted 
metal, a mass of some other matter capable of preserving its form 
under a heat greater than that of the liquid. The latter method is 
on several accounts to be preferred. First we may always use the 

8 


46 Experimental Inquiries respecting Heat and Hapor. 

same amount of hot matter to produce the vapor, and consequently 
compare the actual heats of two melted masses without calculation. 
Second, the hot body may be directly applied to the water without 
the intervention of any enclosing vessel. Third, the pouring of the 
hot metal or liquid into water might not always be convenient or safe, 
as for example when the latter is of greater specific gravity than the 
former. When, for example, oil is laid at a very high temperature, 
on the surface of water, the sudden ebullition of the water, would 
be in danger of causing an explosion that would project the oil up¬ 
wards with great force. 

When we plunge a solid into a melting mass of metal, and allow it 
to remain for some time, it will acquire the temperature of the mass 
of melted matter, but the solid must have certain peculiar properties 
to fit it for this purpose. 

First, it must not melt at a lower point than that of the fluid which 
it is intended to test. 

Second, it must allow ofibeing quenched in boiling water from the 
highest temperatures employed, without cracking, scaling:, oxidizing, 
or undergoing any augmentation of weight by absorbing the liquid. 

Third, it must have as high a specific heat as practicable. 

Fourth, it should be capable of being easily wrought into the pe¬ 
culiar form required for the instrument with which it is to be used. 

Among the substances best adapted for the purpose are the follow¬ 
ing, against each of which the specific heat is marked together with 
the name of the author, whose determination has been followed. 



Spe. Heat. 

Authorities, 

Crown glass, 

.2000 

Irvine, 

White glass, 

.1870 

Wilcke. (.1770, Pet. and Dul.l 

White clay, burnt, 

.1850 

Gadolin. 

Black lead or plumbago, 

.1830 

Do. 

White cast iron, 

.1320 

Do. 

Soft bar iron, sp. gr. 7.724, .1190 

Do. 

Platinum, 

.0314 

Petit and Dulonsr. 


The chief parts of this instrument are a boiler, A; (Fig. 1.)_ a 

stand, S;—a balance beam, D, for weighing the boiler and its con¬ 
tents ; a lamp, L, to heat the water and to maintain ebullition be¬ 
tween experiments; a receiver, R, (Figs. 2 and 3.) and a cylinder 
of metal, I, to be employed as a standard . 


47 


Experimental Inquiries respecting Heat and Hap or. 

The boiler is formed of two concentric cylinders of copper. The 
inner cylinder is two and a half inches in diameter, the exterior one 
is four inches, leaving a space of three fourths of an inch to be filled 
with finely powdered charcoal or lampblack, seen at O, in the sec¬ 
tion (Fig. 2.) 

The interior cylinder rises half an inch above the exterior, which 
is twelve inches high. The former is then expanded into a funnel- 
shaped mouth, F, five inches in diameter at top, and two inches per¬ 
pendicular height, intended to receive and return any portions of 
water which might be thrown up by ebullition, but not converted into 
steam. From the lower part of the apparatus a third concentric 
cylinder, K, rises about three inches and one fourth, where it termi¬ 
nates in a conical head furnished with a pipe, P, passing obliquely up¬ 
wards through the two cylinders before mentioned, and firmly solder¬ 
ed to both. The purpose of this third cylinder is to receive the 
lamp L, and to expose a large surface to the action of its flame, e is 
a stopper intended- to close the pipe, P, when the lamp is withdrawn 
and the experiment in progress. E is an index attached to the sup¬ 
port m, in such a manner that the point E, may be elevated or de¬ 
pressed a few degrees, to correspond to the position of the beam D, 
and save the adjustment by weights before an experiment. The cyl¬ 
inder of lead C, is movable along the rod by means of a screw thread, 
cut the whole length of that arm. This mode of adjustment admits 
of the greatest accuracy, and is liable to less delay than the sliding 
weight. By means of the tightening screw t , the support m m , may 
be placed at any convenient height on the rod r, and by means of s, 
the lamp L, may be loosened and caused to revolve horizontally 
when the metal is about to be immersed; in which case the boiler 
will be for the time depressed, and will rest on the cushion B, which 
is composed of hare’s fur, covered with soft flannel to defend the 
bottom from the access of air; the stopper e, is a further safeguard 
against the same source of loss. A thermometer g , bent at right 
angles, passes through the two concentric cylinders, having the bulb 
directly exposed to the water within, but defended from injury by a 
projection of its tube o, a short distance beyond the inner cylinder. 

The receiver R, is about four inches in height, and one and a quar¬ 
ter in interior diameter, furnished above with a tube 7, and a stop cock 
k, to convey away the steam, and to carry it, when required, into a ves¬ 
sel of cold water. The only direct access of the water x, to the hot 


48 


Experimental Inquiries respecting Heat and Eapor. 

body T, when in place, is through the bottom of the receiver. If the 
stop cock be closed the steam will soon fill all the surrounding space 
and keep the water down quite to the lower edge, but if the cock be 
opened, the steam finding an outlet will rise, and the water will fol¬ 
low and again produce a large quantity of vapor. It will generally 
be found expedient to allow a moderate discharge only at the mouth 
of the pipe, and to cause the greater part of the action to take place 
through the metal of the receiver R. The only uses indeed of this 
part of the apparatus are 1st, to receive, without loss of heat, the 
standard piece I, and deposit it in the water without coming in con¬ 
tact with the exterior air, and 2d, to prevent the dispersion of the 
water by the extreme rapidity of its action, particularly towards the 
close of the operation. The pipe of R, is wrapped with flannel. 

The manner of transferring the standard-piece is seen in Fig. 3, 
where G is a cylindrical or slightly conical recipient either entirely 
closed, or having a few orifices h, h , /?, at the bottom. This recip¬ 
ient is to be formed either of iron, copper, silver, 'platina, plumbago, 
wedgewood ware, or crucible clay, according to the heat to which it 
is to be exposed, or the materials into which it is to be plunged. It 
will often be found expedient to protect the cylinder I, from the di¬ 
rect action of the fused metal, of which we would ascertain the tem¬ 
perature, otherwise there might be an adhesion of some portions of 
the melted mass which would vitiate the experiment. When the 
body 1, has been heated to the requisite degree, and is to be trans¬ 
ferred to the receiver R, the container G, is laid, by means of the 
handle, q, u, on some convenient support; R is then inserted at the 
mouth so that the hook p , shall be on the same side with the handle ; 
G and R are then inclined so that 1 may slide from the bottom of G 
into R, the latter is then rolled over upon the sid e p, when the concave 
base of T, will be received upon the hook, and the cylinder will take the 
position indicated by the dotted figure, the moment R is raised to a 
vertical position. 

It may then be plunged in an instant into the boiling water, as seen 
in Fig. 2. The quantity of vapor produced, is shown by the weights 
W, iv, which it may be necessary to add to A in order to restore the 
position ol the beam, so that the index E, shall again point to an en¬ 
graved line on the side of the bar. 

The receiver R, may be kept in the water when not required for 
immediate use, and be weighed with the liquid both before and after 


49 


Experimental Inquiries respecting Heat and Vapor . 

the experiment. By this means its temperature will be the same as 
that of the water, and no calculation necessary. 

The lamp L, instead of being removed by revolving to allow the 
generator A, to rest on the cushion B, may rise through the center of 
that cushion, which may, in turn, be supported by the rod attached 
at s. This arrangement is seen at B, Fig. 2, where the rod Q, sus¬ 
tains a small circular platform and cushion, as well as the lamp L. 
The advantage of this arrangement is the saving of time, and the 
only inconvenience, that the lamp must be relighted after each ex¬ 
periment, as it will be extinguished by closing P and preventing the 
access of air from below to K. It must obviously not be kept burn¬ 
ing under the generator during the experiment. 

Instead of employing weights as at W, w , to reproduce the counter¬ 
poise, or show the equivalent weight of steam produced, I have gradu¬ 
ated one end or base of the counterpoise C, by radiant lines, and caus¬ 
ed to be removed a segment of about 60° along the screw D, through 
its whole length, so as to present a vertical plane surface, on which 
to form a scale; the graduations of this scale are, of course, regula¬ 
ted by the distance apart of the threads of the screw; the weight 
of the counterpoise is such that one revolution on the thread produces 
a difference of one hundredth of a pound at the boiler end of the 
beam. The periphery of C is then graduated into one hundred equal 
divisions, (indicated by the figures 0, 1,2, 3, &tc.) so that, as a com¬ 
plete revolution of the counterpoise, towards the end of the rod, 
marks an increase of one hundredth of a pound in the weight of 
water put into A, so a corresponding movement in the reverse direc¬ 
tion, compensates for the same amount of loss by evaporation; and 
a movement through one of the centigrade divisions only, or one 
hundredth of a revolution, as marked on the end of the cylinder, of 
course indicates one hundredth of the above amount, namely one 
ten thousandth of a pound. If greater exactness were required, it 
might be obtained either by making the threads at a less distance 
apart, or by diminishing the counterpoise C, and substituting for a 
part of its weight a fixed weight M. 

I have found the apparatus sensible to the fourteen thousandth of a 
pound or half of a grain, when fully charged for use, that is, when the 
boiler contained at least sixteen ounces of water. 

The arrangement above indicated may be varied to suit the differ¬ 
ent purposes to which the instrument may be applied, and the stand- 


50 


Experimental Inquiries respecting Heat and Vapor . 

ards will be different according to the temperatures to which they 
must be exposed. If the substance, of which the temperature is to 
be ascertained, can with safety be plunged beneath the surface of 
boiling water, without causing either chemical change or variation of 
specific gravity, this direct action of the substance is doubtless to be 
preferred to the intervention of any second substance as .a standard. 
The quantity, or number of therms * of heat present, in a given weight 
of the substance in question, will then be known, and if we know or 
can determine the specific heat, we may calculate the temperature 
as already indicated. I have, in this manner, proved the quantity of 
heat present in melted iron. Practical men may, possibly, from oc¬ 
casionally experiencing the tremendous effect of generating a quan¬ 
tity of steam from the moisture of their moulds, imagine that the ex¬ 
periment of pouring melted iron into a vessel of boiling water will 
be attended with danger. But I can assure them, from repeated 
trials, that it is perfectly safe. Plunge into a bucket of water, a 
common small iron kettle, .supported on feet: pour into this, when 
completely immersed, any convenient quantity of melted iron ; the 
ebullition from the surface of the melted mass will be at first very 
slow or scarcely perceptible, while from the outside of the kettle it 
will be very vigorous. The whole will subsequently exhibit the 
same effects as are perceived when a piece of cast iron is immersed 
at a bright red heat. 

The following experiment was made in August, 1831. Twelve 
ounces of melted iron were poured into about six pounds of water, 
at 212° : the result was eight ounces of steam produced. In 
order to calculate this case, and obtain the actual power present in 
the state of heat at the time of the immersion, we have to multiply 
the weight of steam by its latent heat, say 990°, which gives 7920°; 
this divided by the weight of metal, (twelve ounces,) gives G60 for 
the number of ounces of water, which one ounce of the metal would 
have heated one degree, in cooling itself down to 212°. But as the 
temperature of the metal is the thing required, we must divide the 

above by the specific heat of cast iron, say g-^ or .1212, which 

gives 660-e-. 1212 — 5445°. But it will be recollected, that a por¬ 
tion of this must be regarded as the latent heat of melted iron. 


* See Ch. Dupin. Mechanique, tome 3. p. 353, et seqq. 






51 


Experimental Inquiries respecting Heat and Vapor . 

In order to show what the latent heat of cast iron is, we may adopt 
the plan of taking from a mass of melting iron, a lump not actually 
liquefied, quench it, and observe the weight of steam produced. 
Again, pour from the same mass a portion of the liquefied metal, 
and ascertain how much more steam, for the same weight, is given 
by the latter than by the former. The same proceeding may be 
adopted for all other metals and their alloys. 

The following experiments and calculations will show the mode of 
applying the steam pyrometer. 

1 . A cylinder of cast iron, weighing 5668 grs., was heated to red¬ 
ness. It was then placed within the receiver and instantly plunged 
into boiling water, previously accurately weighed ; after the entire 
cessation of ebullition, it was withdrawn and the deficiency supplied 
by weights. The heat had been a moderately red heat;—now, as 
cast iron has a specific heat of about .1212, this multiplied by 5668 
will give the equivalent weight of water =687, which heated to the 
same degree might produce the same effect. In the case just sta¬ 
ted, the quantity of water found to have been evaporated was 674. 
Hence 674 multiplied by the latent heat in steam, ( = 990° Fahr.) 
gives 667260° = the grains of water which would be heated one 
degree by condensing the steam now generated. But as the iron 
was equivalent to only 687 grains of water, it must have been heated 
as many degrees above 212°, as 687 is contained times in 667260°, 
which is 971.2 times; hence this number added to 212° will give 
the temperature of the iron, expressed in degrees of Fahrenheit’s 
scale, equal to 1183.2. 

2 . Another experiment, conducted in the same manner, and with 
the same cylinder, but at a cherry red heat, gave 945 grains of steam. 
By applying to this case the principle of the formula, as before, we 
have, as above, 566S X .1212 = 687, for the equivalent of the iron 
in weight of water; and 945x990 = 935550 = the grains of water 
which would be heated one degree by the condensation of the steam 
produced. Then 935550-f-687 = 1362 = the number of degrees 
which the iron must have lost in producing this effect, while it came 
down from its initial temperature of redness to 212 °. To this again 
we add 212°, and obtain 1574° for the actual temperature. 

3 . A ball of cast iron, weighing 1665 grs., was heated to a bright 
red, and gave 230.2 grains ot steam. Here 1665 X .1212 =201 .8 
= the equivalent weight of water, which, if heated to the same tem- 


52 


Experimental Inquiries respecting Heat and Vapor. 

perature, would have produced the same effect, viz. 230.2x990 = 
227898. Now this divided by 201.8 gives 1128= the degrees 
above boiling point, at which the temperature was at first, or 1128-f- 
212 is equal to the actual temperature abore the zero of F., viz. 1340°. 

4 . With the same ball, a second experiment gave 139 grains of 
steam. Hence 990X 139=137610, and this divided by 201.8=681.8, 
and to this add 212 and we have 893.8 for the temperature at first. 

5. The next experiment was with a cylinder of wrought iron, 
weighing 6110 grains, having a specific heat of .1100, and conse¬ 
quently being equivalent to 6110 X.l 1 = 672 grains of water. The 
observed heat was a moderate red, and the loss in weight of water 
780 grains, whence the temperature must have been (780x990) 
~672=1149-}-212= 1361° Fall. 

6 . The same cylinder was again employed, and raised to a bright 
red, so as to “scale” on exposure to the air. It then gave 989.6 

989.6 X 990 

grains of vapor; consequently its heat must have been-- 

= 1462° above the boiling point, or 1674° of Fahrenheit’s scale. 

The process of calculation may be much simplified, when the spe¬ 
cific heat of the standard piece has been accurately ascertained and 
its equivalent of water found ; for we have then only to multiply the 
weight of steam produced by its latent heat, or heat of elasticity, 
and divide by that equivalent. This is the same as multiplying the 
weight of steam by a known constant fraction. In the fifth experi¬ 
ment above cited, the equivalent of the metal is 672 grains of water, 
so that the constant fraction by which to multiply the weight of steam 
actually generated, in any given experiment with that cylinder of iron, 
in order to obtain the temperature above 212°, is £-ff = Tff> or (in 
decimals) 1.4732. This number, multiplied by 780, gives the de¬ 
grees 1149, as before. The process may be farther abridged, by 
performing the multiplication by logarithms, in which case we should 
have the logarithm of 1.4732 constant, and hence it would only be 
necessary to find in the table the logarithm of the grains of steam, 
add it to said constant quantity, and find the number standing against 
iheir sum , for the temperature above 212°. 

Thus, the logarithm of 1.4732 is .168259 

To which add the logarithm of 780 = 2.892095 

And we obtain the logarithm of 1149° = 


3.060354 





OTEAM FTK-WMBTETR bt W.RoJJ©lunLS®ini 














































































































53 


Experimental Inquiries respecting Heat and Vapor . 

It will be no less easy to solve the same problem by means of a 
Gunter’s scale and a pair of compasses. The distance from 1 to the 
constant fraction, (1.4732 in the above case,) on the line of numbers , 
will reach from the number of grains of steam to the temperature, 
in degrees Fahr., above 212°. 

We might, instead of determining the specific heat of the stand¬ 
ard mass , by the ordinary methods, first heat it to a known tempera¬ 
ture in boiling mercury, in oil, spirits of turpentine, melting zinc, lead, 
bismuth, tin, or any convenient alloy* of these metals, and then ob¬ 
serve the quantity of steam it produces in cooling down to 212°. 
The actual temperature of the liquid being known by observation, 
and the quantity of steam by weight, every other quantity of vapor 
given by different temperatures of the same standard mass, will be 
produced by a proportionate quantity of heat. It will be seen that 
this method of proceeding takes no account of differences in specific 
heat at different temperatures. It comes at once to a simple expres¬ 
sion of the heating power of a body measured by a single effect of 
the heating principle, that of conferring the elastic form on water, 
already raised to the boiling point. 

It will readily be conceived that the question of specific heats, of 
expansion, and contraction, and of course the variable rates of ex¬ 
pansion at different temperatures might be wholly disregarded, if we 
had an invariable standard by which to measure the portions of heat, 
that may at any time be present in a given portion of matter. The 
latent heat of vapor supplies this standard. The following are some 
of the different results which have been obtained by those who have 
made experiments on this subject. 


* The alloys of tin and lead are very convenient lor this purpose. Their mel¬ 
ting points as determined by M. Kupffer, (See Ann. de Chim. et de Phys. XL. 
302; and Thomson on Heat and Electricity, p. 174.) are as follows: 


Tin 

1 atom 

2 « 

3 “ 

4 “ 

5 “ 


Alloy of Lead 


+ 

+ 

+ 

+ 

~h 


1 atom 
L <£ 

1 “ 

1 “ 

1 “ 


Point of fusion, 
466° 

385 * 
367 
372 
- 381 


The alloy commonly employed by tin plate workers is I believe composed of 1 tin, 
j o lead. The mean of several trials with that alloy have convinced me that its 

melting point is 385°. 


9 




54 Experimental Inquiries respecting Heat and Vapor, 


Latent heat in vapor. 

Determined by 

950° 

Watt. 

945 

1000 

Southern. 

Lavoisier and Laplace. 

1040.8 

Rumford. 

955.8 

Despretz. 

- above 1000 

Thomson. 

1000 

mean 984 

Ure, (corrected result.) 


I have in the preceding calculations assumed the latent heat, at 
990°. Should the results of Dr. Ure, which appear to have been 
made in a manner as unexceptionable as any yet published, be con¬ 
firmed and established by other philosophers, the facility of making 
calculations such as I have above presented, will be increased and the 
usefulness of the principle in pyrometry more fully established. 

Note. —The experiment on melted iron, on page 50, is offered 
chiefly as an illustration. The apparatus then at hand did not ad¬ 
mit of all the exactness which the case allows;—still the result is 
believed to be nearly correct. 



From the American Journal of Science and Arts , No. 1. Vol , XXIII. 


\ 

REMARKS 


ON THE 


STRENGTH OF 


CYLINDRICAL STEAM BOILERS. 


13 Y WALTER R. JOHNSON, 

u 


Prof, of JVat. Phil, in the Franklin Institute — Philadelphia. 


Read before the Institute, at the stated monthly meeting, July 26, 1S32. 













































































» 


* 































































































It has been generally supposed that the rolling of boiler-plate iron, 
gives to the sheets a greater tenacity in the direction of the length, 
than in that of the breadth. Supposing this to be correct, it has fre¬ 
quently been asked, how the sheets ought to be disposed in a cylin¬ 
drical boiler of the common form, in order to oppose the greatest 
strength to the greatest strain. It has also been asked, whether the 
same arrangement will be required for all diameters , or whether a 
magnitude will not be eventually attained, which may require the di¬ 
rection of the sheets to be reversed ? 

To determine these questions in a general manner, recourse must 
be had to mathematical formulas, assuming such symbols for each of 
the elements as may apply to any given case of which the separate 
data are determined either by experiment or by the conditions of the 
case. The principles of the calculation require our first notice. 

1. To know the force which tends to burst a cylindrical vessel in 
the longitudinal direction,—or, in .other words, to separate the head 
from the curved sides , we have only to consider the actual area of 
the head, and to multiply the number of units of surface by the num¬ 
ber of units of force applied to each superficial unit. This will give 
the total divellent force in that direction. 

To counteract this, we have, or may be conceived to have, the te¬ 
nacity of as many longitudinal bars as there are linear units in the cir¬ 
cumference of the cylinder. The united strength of these bars con¬ 
stitutes the total retaining or quiescent force, and at the moment when 
rupture is about to take place, the divellent and the quiescent forces 
must obviously be equal. 

2. To ascertain the amount of force which tends to rupture the 
cylinder along the curved side, or rather along two opposite sides, 
we may regard the pressure as applied through the whole breadth of 
the cylinder upon each linear unit of the diameter. Hence the total 
amount of force which would tend to divide the cylinder in halves by 


4 


On the Strength of Cylindrical Steam Boilers. 

separating it along two lines, on opposite sides, would be represented 
by multiplying the diameter by the force exerted on each unit of sur¬ 
face, and this product by the length of the cylinder. But even with¬ 
out regarding the length , we may consider the force requisite to lup- 
ture a single hand , in the direction now supposed, and of one linear 
unit in breadth; since it obviously makes no difference whether the 
cylinder be long or short in respect to the ease or difficulty of sepa¬ 
rating the sides. The divellent force, m this direction, is therefore 
truly represented by the diameter multiplied by the pressure 'per unit 
of surface. The retaining or quiescent force in the same direction, 
is only the strength or tenacity of the two opposite sides of the sup¬ 
posed band. Here also, at the moment when a rupture is about to 
occur, the divellent must exactly equal the quiescent force. 

3 . In order to estimate the augmentation of divellent force, conse¬ 
quent upon an increase of diameter, we have only to consider that as 
the diameter is increased, the product of the diameter and the force 
per unit of surface , is increased in the same ratio. But unless the 
thickness of the metal be increased, the quiescent force must remain 
unaltered. The quiescent forces, therefore, continue the same ; the 
divellent increase with the diameter. 

4. Again, as the diameter of the cylinder is increased, the area of 
its end is increased in the ratio of the square of the diameter. The 
divellent force is therefore augmented in this ratio. But the retain¬ 
ing force does not, as in the other direction, remain the same, since 
the circumference of a circle increases in the same ratio as the diam- 
eter. The quiescent force will consequently be augmented in the 
simple ratio of the diameter, without any additional thickness of 
metal, so that on the whole the total tendency to rupture in this di¬ 
rection will increase only in the simple ratio of the diameter. 

5. Since we have seen that the tendency to rupture, in both di¬ 
rections, increases in the simple direct ratio of the increase of diam¬ 
eter, it is obvious that any position of the sheets which is right for 
one diameter, must be right for all. Hence, there can never be a 
condition, in regard to mere magnitude, which will require the sheets 
to be reversed. 

G. Tbe foregoing considerations being once admitted, we may 
proceed to ascertain what is the true direction of the greatest tena¬ 
city in the sheet, if any difference exist, and to what that difference 
might amount, consistently with equal safety of the boiler in both 
directions. 


On the Strength of Cylindrical Steam Boilers. 


7. Let x— the diameter of the cylinder; f— the force or pressure 
per unit of surface, (pounds per square inch, for example;) T=the 
tenacity of metal, which with the diameter x and the force / will be 
required in the linear unit of the circumference, in order to hold on 
the head. Then, the whole quiescent force will be 3.1416#T, while 
the divellent will he .7354 x 2 f; consequently .7854# 2 /=3.1416#T, 
as above stated. Dividing by .7854#, w T e have xf— 4T; and we de- 

4T 4T xf 

rive immediately x=-jn /=—> T = -j* That is, the tenacity of 


the longitudinal bar of the assumed unit in ividth, will be one fourth 
of the 'product, of the diameter into the pressure , measuring the tena¬ 
city by the same standard as the pressure, whether in pounds or 
kilogrammes. 

8. Now assuming the tenacity required in the circular band of the 
same width to be t, we shall, agreeably to what has already been said, 
have the divellent force expressed by xf and the quiescent by 2 1, so 

xf _ 2t 2 1 


that xf—2,t and also /=—» and j 


Having thus obtain¬ 


ed two expressions for each of the quantities x and f we may by 
comparing them, readily discover the relative values of T and t; 
4T 2 1 4T 2 1 

thus, x=-?r and x—t’ hence and 4T=2 1 or tf=2T. 

/ / f J 

From which it follows, that, under a known diameter , and with a 
given force or pressure , the tenacity of metal in a cylindrical boiler 
of uniform thickness, ought to be twice as great in the direction of 
the curve as in that of the length of the cylinder , and that if this 
could be the case the boiler would still have equal safety in both di¬ 
rections. In whichever direction, therefore, the rolling of the metal 
gives the greatest tenacity, in the same direction must the sheet al¬ 
ways be bent in forming the convexity of the cylinder. It follows 
that if we suppose the tenacity precisely equal in both directions, 
the liability to rupture, by a mere internal pressure, ought to be twice 
as great along the longitudinal direction as at the juncture of the 
head. This supposes the strain regular and the riveting not to 
weaken the sheet. 

9. To know how large w r e may safely make a cylindrical boiler, 
having the absolute tenacity of the metal, in the strongest direction , 
and with a known thickness, we have only to revert to the formula 
2 1 . 

x—~f' That is, the diameter ivill be found by dividing twice the 




6 On the Strength of Cylindrical Steam Boilers. 

tenacity by the greatest force per unit of surface , ivhich the boiler is 
ever to sustain. 

10. When, knowing the absolute tenacity of a metal or other ma¬ 
terial reckoned in weight, to the bar of a given area, in its cross sec¬ 
tion, we would determine the thickness of that metal which ought to 
be employed in a boiler of given diameter and to sustain a certain 

of 

force, we may use the formula t — f* and, dividing the latter mem¬ 
ber of this equation by the strength of the square bar, which we may 
call s, we obtain the thickness demanded in the direction of the curve, 

of 

which we may denominate p , so that p = ^; this will give the thick¬ 
ness of the boiler plate, either in whole numbers or decimals. Thus, 
suppose the diameter of a cylindrical boiler is to be 36 inches,—that 
it is to be formed of iron which will bear 55000 lbs. to the square 
inch, and is to sustain 750 lbs. to the square inch ;—what ought to 
be the thickness of the metal? Here x = 36,/= 750, 25 = 110,000; 

, 36x750 v , , 

consequently, T*" hqqqq — .2454, or a little less than one quarter 

of an inch. 

11. It must, however, be evident that the minimum tenacity, of 
any particular description of metal, is that on which all the calcula¬ 
tions ought to be made, when there is any probability that the actual 
pressure will, in practice, ever reach the limit assigned as the value 
of f in the calculation. 

If we had plates of different metals, or of different known degrees 

of tenacity in the same kind of metal, and were desirous of ascer- 

* 

tabling how strong a kind we must employ under a limited thickness , 

diameter and pressure , we should decide the point by transforming 

xf' xf xf 

the formula P~f s * nt0 P s== g’ anc ^ ^ ien * nt0 s ~2p * ot ^ er terms J 

in order to know the strength of the metal required, or the direct 
strain which an inch square bar of the same ought to be capable of 
sustaining, we must multiply the diameter of the boiler in inches by 
the pressure per square inch in pounds , and divide the product by 
twice the intended thickness in parts of an inch. Thus, how strong 
a metal ought to be employed to sustain a pressure of 1000 lbs. to 
the square inch, in a boiler 30 inches in diameter and one quarter of 



On the Strength of Cylindrical Steam Boilers. 


7 


_ 30X1000 

an inch thick? Here s~ --^~ =60,000. Hence vve see that 

the metal must be capable of sustaining sixty thousand pounds to the 
inch bar, or in that proportion, for any other size. This formula en¬ 
ables us to determine whether among the metals of known tenacity 
any one can be found to fulfil the conditions under the thickness as¬ 
signed. 

12 . On the basis of the foregoing formulas, the following table of 
diameters, thicknesses of iron, and strains to the inch of metal, in both 
directions, has been formed. It is obvious that the actual tenacity of 
the metal employed in a given case must be of the greatest impor¬ 
tance to the result. The extensive series of experiments recently 
undertaken by the Institute to determine this question, in reference 
to different kinds and varieties of boiler plate, and with regard to the 
various circumstances of its manufacture and application, will here¬ 
after furnish us with important data to aid in applying the formulas 
to each separate case. I shall for the present assume the tenacity 
of an inch square bar of rolled iron at 55000 lbs. in the direction of 
the length of the sheet. Supposing the pressure generally employed 
in cylindrical high pressure boilers to be 150 lbs. to the square inch, 
agreeably to the practice in this city, the table is calculated upon the 
principle that the boiler ought to have five times as great a strength 
as it is ordinarily required to exert. The calculation is upon a con¬ 
tinuous sheet of metal, without seams in any direction. The thick¬ 
nesses are given in ten-thousandths of an inch; but in practice the 
last figure may be omitted without material error. 



8 On the Strength of Cylindrical Steam Boilers. 


Diameter o 
the boiler 
in inches. 

Thickness of plate iror 
which will bear 55,00( 
lbs. to the square inch 
required to resist the 
strain in the directior 
of the curve under c 
pressure of 750 lbs. tc 
the square inch, cal¬ 
culated by the formu- 

, x f 

la P = 2s' 

‘1 

Corresponding tenaci- 
i ty of each inch wide 
* ring or band requir- 
i ed to support a press- 
t ure of 750 lbs. to the 
> square inch, calcu¬ 
lated on the formula 

Tenacity required in 
each longitudinal bar 
of one inch wide, to 
sustain the pressure 
tending to burst out 
the head, calcalated 
on the formula T = 

i 

4' 

Inches. 

Inch. 

Pounds. 

Pounds. 

1 

.0068 

375 

187.5 

2 

.0136 

750 

375 

3 

.0204 

1125 

562.5 

4 

.0272 

1500 

750 

5 

.0341 

1875 

937.5 

6 

.0409 

2250 

1125 

7 

.0476 

2625 

1312.5 

8 

.0545 

3000 

1500 

9 

.0613 

3375 

1687.5 

10 

.0681 . 

3750 

1875 

11 

.0745 

4125 

2062.5 

12 

.0818 

4500 

2250 

14 

.0954 

5250 

2625 

16 

.1090 

6000 

3000 

18 

.1227 

6750 

3375 

20 

.1363 

7500 

3750 

22 

.1490 

8250 

4125 

24 

.1636 

9000 

4500 

26 

.1773 

9750 

4875 

28 

.1909 

10500 

5250 

30 

.2045 

11250 

5625 

32 

.2182 

12000 

6000 

34 

.23*8 

12750 

6375 

36 

.2455 

13500 

6750 

38 

.2591 

14250 

7125 

40 

.2727 

15000 

7500 

42 

.2860 

15750 

7875 

44 

.2980 

16500 

8250 

46 

.3116 

17250 

8625 

48 

.3252 

18000 

9000 

50 

.3388 

18750 

9375 


13. Iam not aware that this subject has been previously treated 
in a general manner, at least as it regards several of the points above 
presented. Mr. Oliver Evans made some particular calculations of 


the strength requisite to sustain the pressure in a boiler of known di¬ 
mensions, under a tension of 1500 lbs. to the square inch. In the 














On the Strength of Cylindrical Steam Boilers. 


9 


table at p. 27 of his “Young Steam Engineer’s Guide,” he has given 
calculations for seventeen different diameters of boilers, with the 
power which, at each diameter, the steam would exert “ to break 
every ring of one inch wide in any one place,” and “ the thickness 
of the sheets of good iron necessary to hold the power.” His table 
is formed on the supposition that sheet iron will bear 64,000 lbs. to 
the square inch, and would consequently lead to considerable excesses 
if strictly applied in practice. To six of the diameters he has an¬ 
nexed the “ power exerted on the heads to burst them out, in pounds 
weight.” These he has calculated in the usual manner, by multi¬ 
plying the area by the pressure per inch. Opposite to three of the 
numbers just mentioned, he has added “ the strength of the boiler to 
hold the head on, in pounds weight.” These he has calculated on 
the supposition that the metal had equal tenacity in all directions. 
On this supposition, and on the principles above developed, each of 
those three numbers should have been exactly double of that against 
which it stands in the preceding column. Neither of the three is so, 
precisely; but the first and third come as near it as could be expect¬ 
ed, considering that the thickness is expressed only in hundredths of 
an inch, while the second is too small by more than a million of 
pounds. These errors would not, I apprehend, have occurred had 
the author adverted to the general principle above developed, in re¬ 
gard to strength required of the metal in the two directions. 

The following extract from the table just alluded to, will illustrate 
the preceding remarks: a column of corrected results has been added. 


Diameter of 
the boiler 
in inches. 

Power to break 
each ring of 

1 inch, press¬ 
ure being 
1500 lbs. 

Thickness of 
the plate of 
iron sustain¬ 
ing 64,000 
lbs. to the 
square inch. 

Power ex¬ 
erted on the 
heads. 

Strength to 
hold on the 
heads. 

Corrected num¬ 
bers to be substi¬ 
tuted for those 
of col. 5, agree¬ 
ably to the fore¬ 
going remarks. 

42 

• • 

36 

• • 

20 

31,000 

• • 

27,000 

• • 

15,000 

48 

• • 

42 

• • 

23 

2,077,500 

• • 

1,525,500 

• • 

471,000 

4,052,400 

• • 

2,037,440 

• • 

91S,777 

4,155,000 

• • • 

3,051,000 

• • • 

942,000 


The very general use, in this country, of strong cast iron heads f 
fastened to the wrought iron cylinders by broad flanches extending 
some inches within the latter, there riveted and subsequently further 
secured by a strong wrought iron hoop, driven on when hot and 
shrunk by cooling,—appears to obviate the necessity of examining 
the question in regard to the best form and necessary thickness of 
















10 


Ancient American Utensil. 


wrought iron heads. I have lately seen, at the Philadelphia Water 
Works, the range of boilers, constructed several years ago, on the 
above principle, by Oliver Evans himself, removed, on account of 
their use having been superseded by water power. Although these 
boilers had been for several years employed under a pressure of 100 
and 150 lbs. per square inch, yet the heads did not appear to have 
suffered in the least degree from exposure to this force. Hence the 
French instructions, forbidding the use of plain cast iron heads for 
pressures above l£ atmospheres, do not seem to be founded on suffi¬ 
cient experience of their actual value. 


jYotice of an Ancient American Utensil; by Prof. Walter R. 

Johnson. 

Philadelphia, August 9, 1832. 

TO PROFESSOR SILLIMAN. 

Dear Sir —The early state of the arts among the aborigines of 
this country, is a subject of much interest to the American antiquary. 
Under this impression, I take the liberty of forwarding to you the 
following description, and the accompanying sketch, of an article of 
American manufacture, of a date probably anterior to the time of 
any European discoveries on the North American continent—per¬ 
haps anterior even to the age of mounds and mummies. For the 
donation of this interesting relic of antiquity, I am indebted to the 
kindness of Mr. Isaac Rawlings, of Memphis, in Tennessee. He 
informs me that it was found near his residence, some eight or ten 
years ago, after one of those extensive falls of the river bank, which 
are known to be frequent along the line of the Mississippi. It had 
been buried several feet beneath the surface, and was brought to 
light by the avalanche. The materials of this piece of Indian pot¬ 
tery are blue clay and white particles of a soft, friable substance, 
resembling calcined and pulverized shells. The exterior has neither 
glazing nor coating of any kind, but only such a degree of smooth¬ 
ness as would be likely to result from long use and much handling, 
it does not appear to have been formed upon a potter’s wheel, nor 
indeed to have received the effects of any machinery in its manu¬ 
facture, but the hand which moulded it, must have been not a little 
skilled in the production of such articles, as the figure will sufficient¬ 
ly indicate. Time appears to have produced but little effect upon 




Ancient American Utensil. 


1 1 


3.7 incites 


the materials. The figure will show two slight fractures of the rim, 
and the scaling off of the whole exterior part of the base, except on 
one side. 

At four points, on the upper 
portion of the body, and equi¬ 
distant respectively from each 
other, are four flattened spots, 
each about 1.5 inch in diame¬ 
ter, and, with one exception, 
marked by a darker color than 
the rest of the vessel. Two 



6 6 


of these spots are seen in the ^ 
figure. The depressions were 
obviously made in the moist 
state, and, together with the 
color, may have resulted from 
the arrangement used in burn¬ 
ing or baking the ware; by 
which means these four points were more pressed than others, while 
soft, and less exposed to the fire, w T hen hot, than other parts of the 
vessel. Hence the carbonaceous or other coloring matter, may not 
have been so completely expelled from these parts of the surface. 

Articles of this description must, at a very remote period, have 
been common in that part of the country whence this was taken. 
In the Philadelphia Museum are two jugs or bottles, composed of 
similar materials, found- in Tennessee, at the depth of fifteen or 
twenty feet below the surface of the ground. Several specimens of 
the same ware, are also contained in the collection of the Philo¬ 
sophical Society, in this city. Some of the latter, and one of those 
in the Museum, bear a near resemblance in form to an egg, with 
one end opened and extended a little, to constitute a neck and 
mouth. The most rude and apparently the most ancient specimens 
have generally this form; which may possibly have been suggested 
to the mind of the savage, together with the very idea of earthen 
ware itself, by the previous use of egg shells for some domestic pur¬ 
poses. None of the specimens of pottery above referred to, appear 
to have received any glazing—a remark which, as far as my obser¬ 
vation has extended, is likewise applicable to the Mexican and South 
American pottery. The latter occasionally exhibit a species of var¬ 
nish very durable in its nature, but entirely distinct from a true gla- 











































12 


Ancient American Utensil. 


zing. This observation is in conformity with the opinion of Mr. 
Abraham Miller of this city, whose practical acquaintance with this 
branch of art has led him'to careful examination of many speci¬ 
mens of the ancient manufacture. 

The dotted lines and figures in the cut indicate the several dimen¬ 
sions. That the vessel was not formed by revolving machinery is 
shown by the difference in the depth of the body on two opposite 
sides. The contents of the vase are three and a half pints. From 
its peculiar composition and manufacture, it sends forth when moist¬ 
ened a fresh earthy odor, exactly like that which is perceived at the 
commencement of a sudden shower, at the close of a hot summer’s 
day. As a drinking vessel, this circumstance may have enhanced 
its value in the eyes of the Indian, who thus regaled his sense of 
smell exactly as when he quaffed from the pure native spring. 

I have been thus particular in the above description, from a belief, 
that when collected, figured and described, objects of this kind may 
aid in forming an estimate of the state of the arts and civilization 
among the nations which possessed this continent at periods of very 
remote antiquity, and may perhaps furnish an index to mark the re¬ 
lationship of the American Indians, either with each other, or with 
distant nations of the globe. 

I 


From the American Journal of Science and Arts , No. 2. Vol XXVII. 



ON THE 


METHODS OF DETERMINING AND CALCULATING 


THE 


SPECIFIC HEATS OF CERTAIN SOLIDS, 


WITH SOME PRECAUTIONS TO BE OBSERVED 


IN THE 


EXPERIMENTS. 


BY WALTER R. JOHNSON, 

Professor of Mechanics and Natural Philosophy in the Franklin Institute 
of the State of Pennsylvania. 






















■ y{\ 







• 




• 

• ' , 

















































. 
















/ 




























• 













’ 


V' 





































ON THE METHODS,-&c. 


The practice which formerly prevailed, of presenting to the pub¬ 
lic, statements respecting the results of philosophical experiments 
without a detail of the exact methods adopted for their attainment, 
and the precautions employed to avoid error, has in many instances 
involved the necessity of repetition —long and laborious, of what 
ought, once for all, to have been definitively settled. The verifica¬ 
tion of a philosophical truth, by a method unlike any previously 
employed, is a matter entirely different from the processes just re¬ 
ferred to; and however well we may be satisfied of a truth, estab¬ 
lished in one manner, there will always be found both pleasure and 
profit in attaining the same general conclusions, by methods and 
considerations independent of each other. There is not perhaps 
a better illustration of this remark than the variety of methods which 
may be employed for determining the specific heat of solids. The 
earliest was that of mixture , and consists in immersing the solid at a 
known temperature, in water (or some other liquid,) at a tempera¬ 
ture either above or below its own. The temperature lost by the 
hotter body, and that gained by the cooler, will, with proper correc¬ 
tions, give, when compared, the specific heat of the body under trial. 

The next method, that of Lavoisier, employs, instead of the rise 
or fall of temperature in water, the latent heat of water passing 
from a state of ice and the weight of this solid, which any other 
given solid will melt while cooling from any known temperature 
down to the melting point, is the measure of its specific heat, which, 
being referred to the quantity of ice which a mass of water, equal 
to that of the solid, would have melted in cooling the same number 
of degrees , gives us the numerical expression of the specific heat of 
the solid. 

The third method employs the cooling power of air, and the times 
which will be required to depress the temperatures of the different 
solids through a fixed range of the thermometer are taken as the 
indices of the specific heat. This is the method employed by Pro- 



4 Methods of determining and calculating 

fessor Meyer on the woods and by Prof. Leslie and Mr. Dalton on 
other bodies. 

The fourth method employs the heat which becomes latent when 
water is rapidly converted into vapor at its boiling point , by the di¬ 
rect and sole agency of the solid, heated to a known temperature 
above that point. This method may be successfully employed to 
determine the latent heat of melting metals as well as their specific 
heat from 212° to their melting points, and also their change of ca¬ 
pacity, if any, after they have passed into the liquid state. The 
weight of boiling water which they will under different circumstances 
convert into vapor, compared with the effect of the same amount of 
water, conceived to be heated to the same temperature as the solid, 
gives again the numerical expression of the specific heat. 

It is evident, that if this fourth method be adequate to give the 
specific heat when the temperature is known, it is also competent to 
give the temperature when..the specific heat is known ; but in order 
to remove all doubt as to its applicability to the latter purpose, it is 
well to ascertain by different and independent methods the exact in¬ 
dex of the specific heat, whether uniform or variable, of the solids 
which may be employed for this purpose. Among the substances 
adapted to this end, are pure malleable iron and pure platina. They 
are both highly indestructible, when heated without the access of 
foreign ingredients, such as oxygen, sulphur, carbon, silica, he., and 
though the specific heat of the former is represented by some writers 
as increasing pretty rapidly, with the temperature, yet this increase 
is not by any means in so great a ratio, as that of its dilatations, 
which other authors have proposed to employ as standards for meas¬ 
uring very high temperatures. As to platina, its specific heat is 
low, and its increments of rate, both in dilatation and specific heat, 
are represented as very moderate. I may here remark that the ex¬ 
periments of Dulong and Petit on this subject appear to have been 
erroneously stated in one part of their prize memoir, which has 
doubtless led to the supposition that they discovered no increment 
of capacity in platina by the elevation of temperature. In their ta¬ 
ble of the specific heats of the different metals at 100° and at 300° 
Centigrade, as originally published in the Annales de Chimie, Vol. 
VII, we find .0355 placed under both of those temperatures against 
platina. The same numbers are transferred into every English edi¬ 
tion of works in which I have seen that table, with the single excep¬ 
tion of Turner’s Chemistry, in which the number is .0335 both for 


i 


the specific heats of certain solids. 


5 


100° and 300°. Yet in a subsequent table of the memoir, Petit 
and Dulong have given the indications of thermometers formed of 
the different metals, on the basis of their specific heats, compared with 
those of an air thermometer at 300°, and they have put down that 
of platina 317.9, which it obviously could not be, if its specific heat 
were invariable, but supposing that heat to increase from .0335 at 
100° Cent, to .0355 at 300°, the indication ascribed to it would be 
correct. In a recent edition of Turner’s Chemistry, by Dr. Bache 
of this city, this error has been corrected. 

But, to return to the subject of iron, we find, in the various works 
of philosophers, a remarkable discrepancy between their statements 
of the specific heats of this metal. The following are among the 
results obtained by the different individuals whose names are an¬ 
nexed. 


On iron of sp. gr. 7.876, the specific heat was found, 
“ soft bar iron, sp. gr. 7.724, - 

“ sheet iroD, - 
“ iron, of w r hat quality not specified, 


(< 

do. 

do. 

do. 

- 

- 

- 

(< 

do. 

do. 

do. 

- 

- 

- 

u 

do. 

do. 

do. 

- 

- 

- 


‘ cast iron, abounding in plumbago, 

‘ white cast iron, - 

* iron, (kind not specified,) between 32° and 212° F. 


‘ do. 

do. 

do. 

do. 

32 

“ 392 

1 do. 

do. 

do. 

do. 

32 

“ 572 

‘ do. 

do. 

do. 

do. 

32 

“ 662 


.1260 by Wilcke. 


.1190 “ 

Gadolin. 


.1090 “ 

Lavoisier. 


.1250 “ 

Kir wan. 


.1269 “ 

Crawford. 


.1450 “ 

Irvine. 


.1300 “ 

Dalton. 


.1240 “ 

Gadolin. 


.1320 “ 

do. 


.1098 “ 

Petit and Dulon 

.1150 “ 

do. 

do. 

.1218 “ 

do. 

do. 

.1255 “ 

do. 

do. 


The mean of these thirteen numbers is 0.12377. The wide dis¬ 
crepancies are probably owing to the circumstances under which the 
authors respectively operated, and to physical differences in the 
metal. Nor is the disagreement confined to these results ; for while 
Crawford and Irvine contend that the specific heats of bodies re¬ 
main constant, at all temperatures, Dalton, Dulong and Petit main¬ 
tain that they increase with the increase of temperature. But it 
seems difficult to reconcile this supposition with another result of 
Petit and Dulong, viz. that the specific heat of all bodies is inverse¬ 
ly as their atomic weight, unless we could suppose what is manifestly 
absurd, that the atomic weight varies with the temperature, or that 
in different bodies the rate of increase in specific heat varies always 
inversely as the atomic weight. Thus, if H were supposed the spe¬ 
cific heat of any body and A its atomic weight, and if d H were the 
increment of specific heat for a given rise of temperature, then not 



6 


Methods of determining and calculating 

only must AH=the constant C, but also A(H-f-e?H) must = C / , 
and of course Ac/H = C // ,—in order that another body having the 
atomic weight a, and a specific heat h, should give ah = C, a[h-\-dh) 
=C / , and adh = C ,/ . Let us observe how far their table of the in¬ 
crease of specific heat between 212° and 572° Fahr. will bear out 
this supposition. The atomic weights are those given by Petit and 
Dulong themselves, with the exception of those of mercury and an¬ 
timony, which are derived from Dr. Thomson. 


Metals. 

Atomic weights. 

Petit and Dulong’s 
difference of specific heats 
between 212° and 572° F. 

Values of C" 
from these data. 

Mercury, 

- - 12.5 

- .0020 - 

- .025000 

Antimony, 

i 

i 

cn 

- .0064 - 

- .023100 

Platinum, 

- - 11.26 

- .0020 - 

- .022520 

Silver, - 

- - 6.75 

- .0054 - 

- .036450 

Copper, 

- - 3.957 

- .0064 - 

- .025280 

Iron, 

- - 3.392 

- .0120 - 

- .040704 

Zinc, - 

- - 4.03 

- .0088 - 

- .035464 


To attribute the character of “ constants' ’ to such numbers as are 
found in the fourth column of this table, would be little satisfactory 
to any who were not prone to uphold a theory at all hazards. Even 
the apparent correspondencies between mercury and copper, anti¬ 
mony and platina, silver and zinc, are probably mere accidental co¬ 
incidences. Iron, on which the authors to whom I have referred, 
appear to have bestowed most attention, gives a result far removed 
from all the rest and nearly double to some of them. 

The foregoing considerations, together with the use to be made 
of the specific heat of iron and platina in generating vapor for pyro- 
metrical measurements have induced me to attempt a re-examination 
of certain parts of this subject, and for this purpose I have taken the 
method originally adopted by Wilcke and Black, viz. that of im¬ 
mersing the hot metal in cold water, in connection with the fourth 
method above described, that of using the latent heat of vapor to as¬ 
certain the specific heat when the temperature of the solid is known. 

In experiments of this nature several precautions are to be ob¬ 
served, and a considerable number of sources of error anticipated, 
against which, if we cannot directly guard, we must provide for 
them the necessary corrections. 

1. We must attend to the character and condition of the metal , 
its freedom from alloys or impurities, its specific gravity, its freedom 


7 


the specific heats of certain solids. 

from foreign matter on the surface, particularly from vaporizable 
matters, which may, by being converted into vapor in passing from 
the source of heat to the cold water, essentially diminish the tem¬ 
perature, or, if in any considerable quantity, may aid in elevating 
that of the water, and thus give a result too high. I have been 
sometimes embarrassed by this source of error. In a series of eight 
experiments, made by heating in a bath of oil on a given mass of 
wrought iron, at a mean temperature of 236° Fahr., the tempera¬ 
ture of the room being 76° and that of the water at commencement 
74.86° in a glass vessel of known specific heat, containing at every 
trial the same weight of water, and measuring the temperatures every 
time by the same thermometers, I obtained as the mean result 
.12332,—the lowest being .12131, when the iron was immersed at 
192°, and the highest .12920, when the metal was at only 190°. 

To ascertain how far this source of error would be obviated by 
adopting a bath of mercury, I made eight experiments in the same 
glass vessel, on the same piece of iron, and with all other circum¬ 
stances corresponding to the former set, except that the temperature 
of the metal at immersion was at a mean of 323f°, and of course 
the specific heat, according to Dulong and Petit, ought to have come 
out higher than in the other series, instead of which it was at a mean 
of .12217, the lowest being .12119 at 338°, and the highest .12499 
at 350°, the higher temperature giving the higher result. 

2. The second precaution relates to the condition of the water 
used in the experiment .—The specific heat of saline solutions and 
earthy mixtures being different from that of water, care should be 
taken that only pure water be employed. That which has been re¬ 
cently distilled should be preferred as it is less likely to be charged 
with air than that which has been long exposed in open vessels. If 
any considerable quantity of air contained in the liquid be suddenly 
expanded it may rise to the top and escape carrying with it the por¬ 
tion of heat which has given it so much enlargement of bulk. This 
would cause an error in deficiency. 

3. The temperature and hygrometric state of the air in which 
the experiment is conducted, require attention. It is obvious that if 
we commence the experiment at a temperature below the dew point 
of the air, the vessel will be accumulating moisture before and du¬ 
ring the experiment, and if it remain but for a short time at thejn- 
itial temperature before the hot body is immersed, the consequence 
will be, that the latent heat of the vapor being employed in elevating 


8 


Methods of determining and calculating 


the temperature of the water, the latter receiving from 1000 to 1200 
degrees of heat, for every unit of water condensed, will cause an er¬ 
ror in excess. If however the vessel have remained in its cold state 
for some time, and then received a considerable elevation of tempe¬ 
rature from the hot body, the whole exterior of the vessel will act 
as the wet bulb of a thermometer, and tend to keep the temperature 
of itself and its contents down to the evaporating point. This would 
cause a serious error in defect. Both these errors are obviously to 
be avoided by not allowing the temperature of the vessel to sink be¬ 
low the dew point. In regard to the relative temperatures of the 
vessel and the surrounding air, we must observe that as the latter 
part of the process, when the solid and the water are approaching an 
equilibrium, goes on very slowly, it will be necessary to commence 
our experiment with the water nearly as much below the actual tem¬ 
perature of the apartment as the increase of temperature is expected 
to be, in order to terminate as little as may be above the surrounding 
air. These two conditions of beginning above the dew point and 
never ending much above the temperature of the air can be compli¬ 
ed with only when the air is tolerably dry. Such should therefore 
be the state of weather selected for experiments of this nature. 

4. The construction , magnitude , and specific heat of the ther¬ 
mometer , used to measure the temperature of the water, is an object 
of some consequence in the determination of this delicate question. 
To carry entire accuracy into the subject it will be necessary to 
know the separate weights of the materials which compose it, and 
their several specific heats, and further to allow for an amount of wa¬ 
ter precisely equivalent to that part of the thermometer which is 
immersed during the experiment. In obtaining a thermometer for 
this purpose I caused the tube to be carefully measured and weighed 
before the bulb was blown, to ascertain its weight per inch in length, 
then knowing the length used to form the bulb it was easy to ascer¬ 
tain the number of grains of glass immersed in any given experiment. 
By again weighing after the thermometer was filled, the weight of 
mercury it contained was exactly known, and by weighing the scale 
separately and knowing its specific heat, the equivalent in water was 
found answering to any portion of the whole instrument, which may 
be entered along the scale near the thermometric degrees. The ne¬ 
cessity of allowing for a scale may however be obviated by using a 
naked-bulb thermometer provided the range be sufficient without in¬ 
cluding the naked part of the stem. But to attain this end and at 


9 


the specific heats of certain solids. 

the same time possess the requisite subdivision of degrees the bulb 
must be large, or the stem very long. Could we employ a cylindric¬ 
al metallic containing vessel, fitted up with an apparatus to measure 
its own longitudinal expansions with perfect accuracy, it would per¬ 
haps be the best kind of thermometer for such experiments. The 
specific heat of mercury, at least within the range where a thermom¬ 
eter for our present purpose would be used, is, according to the four 
independent determinations of Lavoisier, Kirwan, Crawford and Du- 
long, .0327. The specific heat of glass given by six different phi¬ 
losophers is at a mean .18511, that of Irvine being .2000, and that 
of Kirwan .1740 at the extremes. By three trials on flint glass in a 
method hereafter to be referred to, I obtained a mean of .17854, 
which is less than the above mean result by .00657 and more than 
that of Dulongand Petit by .00154. 

If the scale be of brass we have its specific heat by the mean re¬ 
sult of Wilke, Crawford and Dalton’s determinations .11276, but as 
the conducting power of that metal is high as well as its rate of ex¬ 
pansion it ought if possible to be avoided as a part of the immersed 
thermometer. 

The thermometer which measures the heat of the solid before 
immersion, should be faithfully compared with that which is used in 
the water. Thermometers of extensive range are often found inac¬ 
curate from containing minute portions of air. It would for this rea¬ 
son be desirable to compare their indications with the fusing points 
of tin and lead, as well as the boiling points of water and mercury. 
To be sure of at least two points in the temperature of the hot body 
it will be well to place it in an iron vessel containing mercury, im¬ 
mersed in boiling water, for that point, and in a bath of melted tin 
immersed in boiling mercury to get the utmost range of temperature 
measurable by that liquid. By forming a suitable covering for the 
bath of mercury, and providing for the exit and condensation of its 
fumes we may operate with perfect convenience in the method just 
described. 

6. I have already mentioned the necessity of confining the range 
of temperature taken by the water during these experiments. If we 
terminate the experiment but one or two degrees above the actual 
temperature of the room the loss by radiation and conduction on one 
side will in general be so nearly counteracted by the gain on the oth¬ 
er, as to influence very little, the actual result. But if we employ 

too small a vessel the high temperature of our solid may give too 

5 


10 Methods of determining and calculating 

great an elevation, and then we shall have not only the radiation and 
conduction of the vessel but the tension of vapor at the surface of 
the water, and the latter will be greater or less according to its great¬ 
er or less distance from the dew-point. The actual absolute loss 
may be found by a separate experiment on exposing the vessel and 
water for some hours to the same temperature as that at which the 
trial took place and in an atmosphere having the same hygrometric 
tension. The weight lost during the longer exposure compared with 
its length of time ought to be proportionate to the loss and time in 
the other case. The number of grains of vapor would then be 
multiplied by its latent heat at the generating temperature, to obtain 
the absolute effect in cooling the mass from which it rose. This er¬ 
ror like that occasioned by the escape of air and that by the evapo¬ 
ration of dew from the surface of the vessel will be in defect. 

7. The nature of the vessel containing the water, its surface, spe¬ 
cific heat and the space it leaves open to the air. It should be of 
such dimensions as to be completely filled when the thermometer 
and the body under trial are immersed in the water. If of metal, its 
perfect homogeneity is to be attained, and if of glass the specific heat 
should be separately ascertained. 

8. To guard the hot body from loss of heat in passing from the 
source of heat to the cold water I make use of a thick sheet-iron 
cylindrical shield which is kept constantly immersed in the melted 
metal with the piece under trial and conveys it to the very mouth of 
the water vessel into which it is lowered by a fine wire or thread ena¬ 
bling the operator to move it from one part of the vessel to the other. 

9. The vessel and its contents must be weighed with the greatest 
attainable accuracy at every trial. No reliance should be placed on 
the apparent levels of the fluid. Graduated measures are entirely 
out of the question in trials of this kind. To adjust the weight with 
readiness I employ a dropping tube with a fine point and instead of 
a piston use a species of micrometer screw, to force out the liquid or 
draw it in at pleasure. Drops weighing one third of a grain may be 
easily obtained by this instrument. The method of substitution is 
adopted in weighing to avoid all inaccuracy in the beam of the bal¬ 
ance. 

10. A result is not to be taken as established until it can be re¬ 
produced, at least, within the limits of the errors of observation. I 
feel assured that much of the erroneous matter which has been pub¬ 
lished on this subject has arisen from a want of due care and patience 


11 


the specific heats of certain solids. 

in repetition. Before closing these observations it maybe proper to 
add, that when in any given experiment the thermometer which 
measures the temperature of the water is withdrawn to insert the 
hot body and afterwards returned to the liquor, it will, under certain 
circumstances of the air, be found to have changed its indication, 
the moisture remaining upon its surface causing it to take the “ evap¬ 
orating point” as its stationary position. In this case it must be no¬ 
ted on again immersing the bulb, and the change it has undergone 
recorded and subsequently multiplied by the equivalent of the im¬ 
mersed part of the thermometer to obtain the requisite correction. 

The table exhibiting the data, calculations and results of experi¬ 
ments to determine specific heats in the manner above described, 
will contain the following particulars. 1st. The number of the ex¬ 
periment; 2d. The kind of heating liquid employed; 3d. The dew 
point of the apartment; 4th. Its evaporating point; 5th. The 
weight of solid under trial; 6th. The temperature at which it is im¬ 
mersed ; 7th. Temperature of the water ; 8th. Temperature of the 
thermometer when immersed ; 9th. Temperature of the air; 10th. 
Resulting temperature of the water; 11th. Gain of temperature by 
the water containing vessel and thermometer; 12th. Loss of tem¬ 
perature in the solid ; 13th. Time occupied by the experiment; 
14th. Weight of water in grains; 15th. Equivalent of the contain¬ 
ing vessel in grains of water ; 16th. Equivalent of the part of ther¬ 
mometer immersed ; 17th. Sum of the equivalents in water, con¬ 
taining vessel and thermometer; 18th. Product of the preceding 
column by the gain of temperature; 19th. Product of the weight 
of solid by its loss of temperature; 20th. Correction obtained by 
multiplying the equivalent of the thermometer by its variation from 
the initial temperature of the water. (This correction will be either 
positive or negative, according as the evaporating point is below or 
above the initial temperature.) 21st. Specific heat obtained by di¬ 
viding the 17th column, corrected , by the 18th. Other corrections 
may be inserted when necessary according to the observations already 
made. To present the several cases to which we have referred in 
the preceding remarks, the following formulas may be adopted. 

1. When the specific heat of the containing vessel is to be ascer¬ 
tained by first filling it with water of a known temperature and letting 
it stand until we are sure that a stationary point has been attained, 
then emptying it and instantly refilling with water of a different tern- 


12 


Methods of determining and calculating 


perature; if the expansion of the vessel could be made to measure 
its own increase or diminution of temperature we should have the 
simplest of all possible cases ; for calling 
iv = the weight of water in grains, 

T= the degrees of change in temperature which it undergoes, 
g= the weight in grains of the containing vessel, 
t= the change of its temperature by the experiment, and 
x— the specific heat of the material of which the vessel is com¬ 
posed, that of water being unity, we shall have TW =gtx or a?= 


TW . . . 

—— (1). This supposes the experiment to be made with such re- 
6 

gard to the thermometric and hygrometric state of the air as to re¬ 
quire no correction on that account. 

2. If we introduce a mercurial thermometer, with a brass scale, 

to measure the change of temperature, putting v 

b = the weight of brass immersed, 
m— the weight of mercury, 

c— the weight of the glass bulb and that part of the stem which 
sinks into the water, we have, for the equivalent of the thermometer 
ingrains of water, the following expression, .11276 b -f .0327 m-\- 
.18511c, and as by suspending the thermometer or otherwise fixing 
it in a certain position for many experiments, we can always use the 
same part of its length, we may substitute for this complex term the 
simple expression c for the thermometrical equivalent in grains of 

T(W-J-c) 

water; then the formula (1) will become x= ---(2). It was 

by this method of trial and calculation that the three experiments 
before mentioned, gave .17854 for the specific heat of glass, though 
in the expression for the thermometer I have chosen to use the mean 
of six other determinations until I can repeat and vary the experi¬ 
ment, so as to be satisfied which is nearest to the truth. 

3. The specific heat of the containing vessel being known, we 
proceed to that of any other solid, wrought iron for example, putting 
its weight in grains —i, and its specific heat =£. T will now rep¬ 
resent the change of temperature not only of the water and ther¬ 
mometer but also of the containing vessel, and t the change of the 
solid, i, g, x and e being the same as above, then will itz — r T{w-\- 

gtf-J-e) and z— - jf - (3), or the formula may be simplified 






the specific heats of certain solids. 


13 


TW X 

by representing the three terms w-{-gx-\-e by W' whence g = 

• tv 

(4). To this, as before stated, we must apply a correction if the 
thermometer be not at the same temperature when immersed, as the 
water was when the solid was plunged into it. Calling the differ¬ 
ence d we have the correction tde, as before stated, according as 
the thermometer was below or above the water, and hence the form- 

Tw'tde 

ula becomes x =-r-— (5). 

it v ' 

4. If the specific heat of the solid under trial and of the contain¬ 
ing vessel be the same, (as when a vessel of untinned sheet iron is 
employed to hold the water,) we may then if the specific heat be 
supposed not to vary within the limits of our experiment, employ the 
following expressions in which z is the specific heat of both, the 
solid and the water vessel; T, w, and e remaining as in (3), we ob¬ 
tain the equation itz=’T(w-\-e-\-gz')— T T(w-\-e) -f- Tg*z, and by 

T(rc-f-e) 

transposition itz— Tgz=T(w-{-e), whence z—— (6). 

it—g L 

5. But if, instead of making the container of the same material 
as the body under trial, we choose to form it of any other kind, even 
of one whose precise specific heat is not yet known, we may, by 
using vessels of different thicknesses and the same liquid content, 
ascertain by successive experiments under otherwise similar circum¬ 
stances, the specific heat of the material which composes the vessel. 
Thus two jars capable of containing the same weight of water may 
be formed of glass from the same melting pot, but one possessing 
two or three times the thickness of the other. We may then heat 
the same mass of iron twice (or any number of times) to the same 
temperature, and immerse it in water at the different trials in each 
of the two vessels at the same temperature. Then putting 

w= the weight of water contained in each glass, 
g— the weight of the thicker glass, 
g'= that of the thinner, 
x= the unknown specific heat of glass, 

T= the change of temperature of water and glass when g is used, 
t— the change of temperature of iron when g is used, 

T'= the change of temperature of water when g' is used, 
t'= the change of temperature of iron when g' is used, 
i, as before, = the weight of iron, 





14 


Methods of calculating and determining 


z= its specific heat, 

e— the equivalent of the thermometer. 

Then, as the temperature of the water, the air, and the iron, are 
supposed to be the same in both cases, we shall have by the two 
expressions, 

TW 'tde T (w-\-e-\-gx)tde 


1. z = 


and 2. z— 


it it 

Id'w'tde lifiu-^e-l-g'x^tde m 


Hence 


it' ~ it' 

from which we derive 

T (we)-{-Tgxtde f T'(w-\-e)-\- r Y'g'xtde 

4. Tt'(iv-\-e) -{-Tt'gxtdet' =-T't(w-{-e)-{- r T'tg'xttde, and by 
transposition, 

5. Tt'gx—Id'tg'x — (Id't — T^) . (we)t(tZt '). de, and by 
division, 

(T't — lit '). (w-\- e')t(t^.t') de 


6 . X : 


T^ 


Tig 1 


which, if there be no cor¬ 


rection for thermometric variation, will be reduced to the simpler form, 
(T't — Tt') ,(w-\-e) 

7. x—- -rp ; —j (7). And as the value of# is now 

§ <b 

found, we may substitute it in either the first or second equation, to 
enable us to find the value of z. The first would give, (omitting 
the correction tde,) 


8. z— 


[(T't—Tt').(w-\-e 

T ( w + c ) + ( Tfg^TFTg 7 


tl 


Had we taken the 


second equation in which to substitute the value of x, the value of z 

V —T^Q • 


would have been = 


T 7 (w 4- e) +T'g' ^ _ T /^/ 


t'i 


From 


either of these we may obtain 

9 g _^Cg-gQ-(y±£l. / 8 x 

i(Tt'g-T'tg') 

The necessity of applying the correction d -de, arises from the lia¬ 
bility of the warm current of liquid ascending from the hot metal 
to elevate the temperature of the thermometer above that which 
ought to be exhibited by the liquid when the maximum effect of the 
solid has been attained. By taking the thermometer out of the 

















the specific heats of certain solids. 


15 


water at the instant the metal is immersed, and keeping it out till 
near the conclusion of the experiment, we not only have a better 
opportunity to agitate the liquid, but also avoid the deception just 
referred to. 

If the experiment be commenced precisely at the evaporating 
point , the bulb of the thermometer covered with a film of water will 
be retained at that point and no correction required. 

The formula for the fourth method of determining specific heat, 
which may serve as a verification of the one just presented, is found¬ 
ed on the fact that the weight of vapor generated by a given weight 
of metal is proportionate to the weight , temperature , and specific 
heat of the metal employed. The experiments in this case all ter¬ 
minate at the boiling point, but may commence at any known supe¬ 
rior temperature. The result obtained will therefore be the mean 
specific heat between the temperature of boiling water, and that at 
which the metal enters the liquid. Calling 
i — the weight of metal employed, 

t = its temperature above boiling point at immersion, and 
z — its mean specific heat, from boiling point to the temperature 
at which it is immersed; also, 

D = the weight of vapor produced by the action of i, and 
l = the latent heat of vapor from water boiling in the open air at 
the time and place of the experiment. 

Then, by the above statement, we have (supposing no heat lost 
by any other means than vaporization) the effect =vl, and the cause 
=it. The latter is on the supposition that the experiment ceases, 
and the loss of weight in water is ascertained, the moment the metal 

. vl 

has come down to the boiling point. Hence itz=vl, and z——• (9.) 

Also, as above stated, the temperature t can be found when z is 

vl 

known; thus, t=-. — (10.) 

X z 

Collecting the foregoing formulas into a single view, we have the 
following table. 


16 Methods of determining and calculating specific heats , &fC. 


No. of the 
formula. 

(!•) 

( 2 .) 

(3.) 

( 4 -) 

(5.) 

( 6 .) 

(■?•) 

( 8 .) 

(9.) 

( 10 .) 


Purpose of the experiment 
and calculation. 

To find the spec, heat of a con¬ 
tainer, measuring temperature by 
its own expansion. 

To find the same when a mer¬ 
curial thermometer is used. 

To find sp. heat of a solid, and 
correcting for the water vessel. 

To express the same, reducing 
water, thermometer, and contain¬ 
er to W 7 . 

Do. corrected when the ther¬ 
mometer differs from initial tem¬ 
perature. 

Do. when the container is of the 
same material as the solid under 
trial. 

To find sp. heat of the container, 
by trials in two vessels of unequal 
weights, 

To find sp. heat of the solid from 
the same trials as the preceding. 

To obtain the sp. heat of a solid 
from its vaporizing power. 

To find the temperature of the 
solid by vaporization when the 
specific heat is known. 


Expression in terms 
above explained. 

) T w 

S gt 

) TO + e) 

5 gt 

) TQ- f e±gx) 

\ Z ~ it 



TW'± de 

: it * 


T (w-\-e) 

(T't-Tt').(w-\-e) 
Tt'g — T'tg' 

TT'(g-g').(u>+e) 
5~ i(Tt'g-T'tg' 

1 vl 
> Z=~-• 

5 it 

vl 

IZ 



Numerous experiments on all branches of the subject have al¬ 
ready been made, and others are in progress, the whole of which 
will in due time be laid before the public. 












On the fusing point of Zinc , and a reference to 
the relation between the tenacity and the fusi¬ 
bility of the metals in general. By Walter 
R. Johnson, A. M., Mem. Acad. Nat. Sci. 
Phila., Prof, of Mech. and Nat. Phil, in the 
Frank. Inst., &c. 


Read Nov. 1st, and 22d, and Dec. 6th, 1836. 

The elevated temperature at which zinc is fus¬ 
ed, and the imperfection of the means formerly 
employed to determine the melting points of the 
more obdurate metals, prevented the attainment 
of the same precision in regard to it, which was 
found practicable in the case of lead, tin, bis¬ 
muth and their alloys. 

Guyton Morveau, by means of his platina 
expansion pyrometer, had fixed the melting point 
of zinc, at 705.25 degrees of Fahrenheit. His 
instrument depended for its action on the differ¬ 
ence in the expansions of a plate of baked porce¬ 
lain and one of platina. That his determination 
of the melting point of zinc is inaccurate, may be 
inferred from the fact, that he places the tempe¬ 
rature of red heat in daylight at 517° Fahrenheit; 


2 ON THE FUSING POINT OF ZINC, &C. 

whereas, it is well known that redness does not 
begin to appear, even in the dark, until we have con¬ 
siderably exceedecF tH^ boiling point of mercury; 
which, measured by the % expansion*'of^hjft*ltqfuM,4 
corrected for the dilation of glass, was found by 
Mr. Crichton, to be 660° Fahrenheit. 

Mr. Daniel measured the expansion of zinc 
from 62° to 212°, and from 62° to 662°, as also 
from the first mentioned point to that of its fu¬ 
sion,—and taking the amount of the two former 
expansions as the measures of the temperature of 
fusion, he found it to be 848°, when the expansion 
to 212° was applied; and 960°, when that to 662° 
was taken for the standard. On applying to this 
metal, however, his pyrometer, which is founded 
on the difference of expansion between platina and 
plumbago, he found the degree indicated for the 
fusing point of zinc to be 773°; thus differing from 
Morveau by an excess of about 68°, while in his 
determination of the fusing point of other metals 
of high melting points, he falls below Morveau. 
In the case of cast iron, this difference amounts 
to 5217 degrees; Daniel giving for the fusing 
point of that metal only 3479°, while Morveau 
gives 8696°. In the publications of the Society 
for the Diffusion of Useful Knowledge, the fusing 
point of zinc is said to be 700°. Having, in the 
course of some investigations with the steam py- 


ON THE FUSING POINT OF ZINC, &C. 3 

rometer, become satisfied that the temperature 
at which iron is distinctly red in daylight, is 
stated too low by the writers on that subject, and 
that the temperature of melting zinc is rather be¬ 
low than above that point, I felt desirous of test¬ 
ing the correctness of the generally received state¬ 
ments. 

With this view, several experiments were made 
by plunging the standard piece of the pyrometer 
into a mass of melted zinc, contained in a cylin¬ 
der of wrought iron; continuing it there for 15 or 
20 minutes, allowing the iron container and the 
zinc in the mean time to be kept just above the 
temperature of fusion, so that the standard piece 
could be withdrawn without impediment. When 
taken from the melted mass, some portion of zinc 
usually adhered, much the greater part of which, 
however, was readily removed by a smart blow or 
two given with a rod of iron to the standard piece 
while suspended by the wire. The portion (usual¬ 
ly a few grains,) which still continued to adhere, 
served, by solidifying, to show the moment when the 
iron had cooled to the point of the congelation of 
zinc. When that was attained, the standard piece 
was plunged into the boiling water of the pyrome¬ 
ter, the weight of vapour which escaped was ascer¬ 
tained in the usual manner, and the quantity of 
zinc which adhered was subsequently found, by 


4 ON THE FUSING POINT OF ZINC, &C. 

weighing the standard piece with the pelicles of 
zinc still adhering, and deducting its previous, 
known weight. This was then added to the ap¬ 
parent weight of vapour which had escaped, and 
by allowing a correction for the weight of adher¬ 
ing zinc and its known specific heat, it was easy 
to arrive at a just calculation of the temperature 
of the iron at the moment of immersion. 

In this manner were made several successive 
trials, in neither of which did the standard piece, 
at the time the zinc ceased to be fluid upon its 
surface, present the least luminousness in daylight, 
but as it had been a little before withdrawn from 
the bath of melted zinc, which had just ceased to 
appear luminous, it is conceived that this point 
could not be far remote,—probably not more 
than 100 or 150 degrees. 

In the first experiment, the number of parts of 
vapour read from the revolving counterpoise 
was 776; the number of parts of zinc adhering, 
105; for which the correction to be added to the 
observed weight is 92; and as the experiment, in 
all cases, terminates at 212°, this number is to be 
added to the sum of the others in order to obtain 
the fusing point on Fahrenheit’s scale = 1080°. 
Suspecting that the immersion might have been 
made a little too soon, or before the true solidify¬ 
ing point had been attained, I made a second trial, 


1 


5 


ON THE FUSING POINT OF ZINC, &C. 

in which the iron was not immersed until it was 
so far cooled as to prevent the adhering zinc from 
being scraped off with a knife. This trial yield¬ 
ed the result of 953° for the melting point; con¬ 
ceived to be too low. 

A third trial, in which the efforts to remove the 
zinc were not persevered in quite so long as in 
the preceding case, gave 1032°. Admitting the 
possibility that the last experiment was still a 
little above the truth, we may combine it with 
the preceding, to obtain a mean for the approxi¬ 
mate temperature of melting zinc, viz.: 993°. 

If we knew any temperature at which heat 
ceased to exert an influence adverse to the cohe¬ 
sion of a metal, that point might obviously be as¬ 
sumed as the maximum of tenacity; and, as at the 
point of fusion all tenacity is overcome, the gra¬ 
dual advance from no tenacity to the maximum, 
might be marked by the degrees of heat below the 
point of fusion at which trials of tenacity are 
made; since it is obvious that whatever mechani¬ 
cal force we apply to overcome tenacity will be 
so much less than the force at maximum tenacity, 
as the quantity of heat employed to assist us is 
the greater. It will be my object, in the suc¬ 
ceeding part of this paper, to trace, at least ap¬ 
proximately, the law of tenacity, as dependent on 
this principle, in some of the more fusible metals. 


6 ON THE FUSING POINT OF ZINC, &C. 

The metals selected were tin, lead, bismuth, 
and an alloy of tin and lead. On these four ma¬ 
terials were made several experiments at or¬ 
dinary temperatures, and, on some of them, other 
trials, at points above or below the range of at¬ 
mospheric variations. 

Experiment 1. The first experiment was on a 
bar of stream tin, cast, at a temperature not much 
above the melting point, into a mould one foot in 
length, of uniform area of section throughout its 
length. The figure of the cross section was a 
trapezium, the two opposite and parallel sides 
having lengths differing about one inch from each 
other. The area of this cross section was 
. 385595 . —This bar required to draw it asunder 
2417.5 lbs., equal to 6282 lbs. per square inch. 
The area of the section of the fracture was 
.26714 of a square inch, and the amount of constric¬ 
tion, consequently a little more than | of the whole. 

Exp . 2. This experiment was made on a dif¬ 
ferent bar from the preceding. In order to reduce 
the temperature of the bar below that of the air, 
it was enclosed in snow closely packed around 
the bar, leaving only a small portion of each end 
projecting, for the purpose of attaching it to the 
opposite parts of the machine employed as a test. 
When connected, the coupling parts of the appa- 


ON THE FUSING POINT OF ZINC, Ac. 7 

ratus, as well as the bar, were surrounded with 
snow closely packed, and the whole wrapped with 
several folds of linen cloth, to sustain the snow 
and guard in part against radiation and the con¬ 
tact of the air. Having allowed sufficient time 
for the whole apparatus to attain a uniform tem¬ 
perature, the force was applied, and it was found 
that the fracture took place much more slowly 
than in the first experiment, and gave a result of 
6504 lbs. per square inch. 

Exp. 3. In order to guard against any error 
which might be assigned to the last experi¬ 
ment when compared with the first, in conse¬ 
quence of the two having been made on different 
specimens of the cast tin, I now caused the ma¬ 
chine to take hold of another part of the bar, 
which had been broken at 32°, and, on applying 
the weights at a temperature of 50°, it gave way 
with a force of 6258 lbs. per square inch. 

Exp. 4. At the temperature of 50° the same 
bar again gave a result identical with that which 
had been obtained in the first trial, viz.: 6282 lbs. 
per square inch. 

In all these experiments, it was observed that 
the section of fracture was irregular and jagged 
throughout. 


8 ON THE FUSING POINT OF ZINC, &C. 

In comparing the experiments of Mr. Rennie 
with the mean of 3 of those above cited at 50°— 
52° of temperature, we find a difference of no less 
than 1538 lbs. per square inch, by which the result 
of that experimenter falls short of that which I have 
obtained. The result of Mr. Emerson was very 
near that above given, viz.: 6255. 

In seeking the cause of such discrepancies as 
that between Mr. Rennie and myself, we must 
look to other grounds than the accidental impuri¬ 
ties of the metal, or varieties in the mode of ap¬ 
plying the force. It is probably to be found in 
the temperature at which the bars were severally 
cast. 

Exp . 5. Another bar, having a cross section 
of .405816, was cast at a somewhat higher tempe¬ 
rature than the preceding. When tried, it was 
found to yield a result of 6040 lbs. per square inch. 
In the course of the operation upon this bar, it 
was observed that the first permanent elongation 
did not take place, until rather more than f of the 
breaking weight had been applied. In order to 
render the influence of the casting temperature 
still more unequivocal, I cast several bars, at 
temperatures varying from that already described 
to a bright red heat. The result was, that a gra¬ 
dual diminution of the tenacity of the bars when 





ON THE FUSING POINT OF ZINC, &C. 


9 


cold was observed, conforming apparently to the 
slowness with which the metal finally became 
congealed, and the consequent perfection with 
which the crystalline arrangement was allowed to 
be assumed. 


Exp. 6, 7, 8. On three several bars cast very 
hot, but below redness, were obtained the follow¬ 
ing results, viz.: 

1 at 52° exhibiting strength of 5208 
1 at 62 “ “ 5174 

1 at 66 “ “ 5174 

Mean of the three 5185 

In all these cases the fracture exhibited regular 
crystalline arrangements, particularly in the inte¬ 
rior portion of the section. The outer coat of the 
metal was however generally amorphous, and as 
the force was very gradually applied and could at 
pleasure be arrested before the exterior coat of 
fibres parted, the latter often exhibited the ap¬ 
pearance of a hole quite through the bar in the 
direction of its thickness, the fibres at the edges 
and corners still continuing to retain their hold 
and extend themselves after the central, and more 
perfectly crystalline mass had given way. An¬ 
other interesting circumstance was also observ- 



10 ON THE FUSING POINT OF ZINC, &C. 

able; the crystalline arrangement had a dividing 
plane cutting the centre of the bar in the direc¬ 
tion of its breadth. 

Exp. 9. A bar was cast at a temperature 
above redness into the mould previously heated, 
hut below the melting point of tin. This bar 
gave a result of 5062 lbs. per square inch, at the 
temperature of 59°. Hence it appears that the 
influence of casting temperature may extend to 
about ~ of the tenacity of that which is cast hut 
little above the melting point, the higher casting 
temperatures giving the lower tenacities. 

In order to compare the experiment at 32° with 
those which were subsequently made on hot-cast 
bars, it is necessary to do it through the medium 
of those trials at 50°—52° which were made on 
bars of the same character as the one tried at the 
freezing point. Thus 6274 : 5185 : : 6504: 5375= 
the strength of the hot-cast bars at 32°. 

Having thus in some measure ascertained the 
effect of the mode of preparing the specimens, I 
proceeded to investigate the tenacity of bars cast 
at a high temperature, when subsequently heated 
above the ordinary range of the atmosphere. For 
this purpose the bars were made to pass through 
a bath of water kept hot by a spirit-lamp. 


ON THE FUSING POINT OF ZINC, &C. 11 

Exp. 10, 11, 12. In this manner were made 
three experiments; one at 122°, giving a strength 
of 3510 pounds per square inch; and two others, 
at 212°, giving respectively 2476 and 232S pounds; 
mean 2402. The elongation of the bars was, in 
these cases, confined to the part in the hot water. 
The nature of the fracture was similar to that ob¬ 
served on the hot cast bars, when tried at low 
temperatures. From what has just been stated, 
it is evident that at 122° the strength of tin is but 
little more than three-fifths of what it is at 60°, 
and at 212° it is less than half as much as at 60°. 
In accordance with what has been already stated, 
we may now consider the difference between the 
melting point of tin and each of the above tem¬ 
peratures, as a series of quantities, corresponding 
with which is another series representing the te¬ 
nacities at those temperatures respectively. It is 
evident that if the tenacity be a simple function of 
the temperature below the melting point , two 
points will be sufficient to establish the law, but 
if it be found that the function itself is variable, in 
other words, that the curve representing the cor¬ 
respondencies between the temperatures and te¬ 
nacities has a point of inflection, we shall be only 
able to examine it by discussing several points 
on each side of the inflection. I will first present 
a table of the experiments thus far detailed. 


12 ON THE FUSING POINT OF ZINC, &C. 


No. of ex- | 

periment. | 

— - . 

Mode of casting. 

Area of sec¬ 
tion. 

Temper¬ 
ature at 
time of 
trial. 

Strength 
in Ibs.per 
sq. inch. 

Date. 

1 

Cool, into 
cold mould. 

.385595 

52° 

6282 

1836, 
March 5 j 

2 

do. 

do. 

32° 

6504 

do. 

3 

do. 

do. 

50° 

6258 

do. 

i 4 

do. 

do. 

50° 

6282 

do. 

5 

do. 

.405816 

52° 

6040 

March 7 j 

1 

! 6 

Very hot, not 
red. 

.385595 

52° 

5208 

do. 

7 

do. 

do. 

61° 

5174 

April 2 

8 

do. 

do. 

66° 

5174 

April 9 

9 

Red hot into 
hot mould. 

do. 

59° 

5062 

April 17 

10 

Hot, not red. 

do. 

122° 

3510 

April 2 

11 

do. 

do. 

212° 

2476 

do. 

. 

12 

1 

i 

. 

o 

-a i 

l 

1 

| 

do. 

212° 

2328 

do. 


By comparing the above calculated result on a 
hot-cast bar, broken at 32°, with the experimen¬ 
tal results on the same bar, broken at 60°, as de¬ 
duced from experiments 6, 7 and 8; at 122°, as 
given by experiment 10; and at 212°, as obtained 
from the mean of experiments 11 and 12, we get 
the following series of temperatures below melt¬ 
ing point, the correspondent tenacities in pounds 
per square inch, and the function of temperature 


/ 


















































































ON THE FUSING POINT OF ZINC, &C. 13 

below fusing point, which represents the tena¬ 
city. 


No. of the 
comparison. 

Tempera¬ 
ture of the 
experiment. 

Degrees be¬ 
low the fus¬ 
ing point of 
tin. 

Tenacities 
in lbs. per 
square inch. 

L og. of the 
degrees be¬ 
low fusing. 

Log. of the 
tenacity. 

Power of 
the tempera¬ 
ture repre¬ 
senting the 
tenacity. 

i 1 

1 

32 

410 

5375 

.6127839 

.7303785 

1.206 

2 

60 

382 

5185 

.5820634 

.7147488 

1.409 

3 

122 

320 

3510 

.5051500 

.5453071 

1.690 ; 

4 

212 

230 

2402 

.3617278 

.3805730 

1.352 


The above powers of the temperature, which 
represent the correspondent tenacities at the dif¬ 
ferent parts of the thermometric scale, are derived 
from a comparison of each experiment with every 
one of the others, by the formula ; 

where <p is the power sought, t a given distance 
on the scale of temperature below the fusing 
point, t' another, but less distance below the 
same point, c the cohesion at the temperature 
t, and c' the cohesion at t'. It has sometimes 
been supposed that a certain relation existed be¬ 
tween the temperature of fusion, the tenacity, and 
the specific gravity of metals. In order to test the 
correctness of this supposition, I made a few expe¬ 
riments on other metals, the melting points and 
specific gravities of which are known. It has been 
shown above, that the law of tenacity for tin, as 
dependent on temperature, is not a simple rela - 













































14 ON THE FUSING POINT OF ZINC, &C. 

tion , identical throughout the scale; and the fus¬ 
ing points of different metals are at different dis¬ 
tances from the ordinary temperature of the air. 
Their laws of tenacity, commencing from their re¬ 
spective melting points, may also be different one 
from another; and even if alike, still two metals 
must, at any assumed point of the scale, be found 
at very different distances apart, from what they 
would be at another point of the same scale. 

From these considerations, it is easy to foresee 
that if it should so happen that the specific gravity 
of a metal multiplied by its tenacity at one tempera¬ 
ture, gave a product representing its fusing tem¬ 
perature, and that another metal should have such a 
tenacity at the same point, and such a specific gra¬ 
vity as, when the two were multiplied, would give 
a result corresponding to its melting temperature, 
still it would not follow that at all other tempera¬ 
tures the tenacities multiplied by the respective 
specific gravities, would give results proportionate 
to the same quantities, that is, to the fusing tem¬ 
peratures. 

If the tenacity of tin, as a solid, were taken at 
442°, it would be found 0; but that of lead, at 
the same temperature, being 170° below its melt¬ 
ing point, would be an appreciable quantity, pro¬ 
bably not less than one-sixth or one-eighth of 


ON THE FUSING POINT OF ZINC, &C. 15 

its cohesion at 60°. Again, the cohesion of mer¬ 
cury at —39° is 0; below that point, it becomes 
sensible, and probably goes on increasing accord¬ 
ing to some law, with the decrease of tempera¬ 
ture; iron at —39° is, according to the generally 
received opinion, weaker than at +32°; in other 
words, it has, if this opinion be correct, passed its 
maximum of tenacity, by an abstraction of heat, 
before mercury has begun to receive tenacity by 
the same means. The specific gravities of the 
two substances have, in the mean time, undergone 
no such change as essentially to affect the pro¬ 
duct obtained by multiplying it by the tenacity . 
jn the following table, the tenacities, excepting 
for zinc and silver, were obtained from my own 
experiments. The fusing points of the first three 
metals in the table are derived from other ex¬ 
perimenters ; that of wrought iron is taken from 

the mean of two experiments by different methods, 
given by Clement and Desormes, who used for 
measures , the melting of ice, and the heating of 
water, in the two cases respectively. The other 
melting points, viz.: those for zinc, copper, silver, 
cast iron, and the alloy of tin and lead, are the re¬ 
sults of my experiments, principally with the 
steam pyrometer. 


16 ON THE FUSING POINT OF ZINC, &C. 


Experiments . |j 

Names of me¬ 
tals. 

Tenac ity at 60 d. 
Fahr. in tbs. 
per sq. inch. 

Specific gravity 

at 60 deg. 

Fusing point by 

experiment. 

Fusing point by^ 

Cloud's formula 

F—TD. 

i 

i 

Specific heat of 

the metal. 

Atomic weight 

of the metal. 

J 1 

1 

Bismuth. 

2328 

9.880 

506 

269 

.0288 

71 

2 

Lead. 

3215 

11.385 

612 

426 

.0293 

103.6 

3 

Tin. 

5185 

2.799 

442 

442 

.0514 

57.9 

4 

Zinc. 

2600 

7.000 

993 

212 

.0927 

32.3 j 

5 

Copper. 

32.826 

8.986 

2828 

3445 

.1043 

31.6 

6 

Wrought 

iron. 

57.525 

7.77 

3945 

• 5220 

.1133 

28. 

7 

Alloy,* tin 
and lead. 

1 T.+3 L. 

3.991 

9.944 

514 

463 



|8 

Pure silver. 

41.500 

10.470 

2194 

5074 

.0557 

108. 

9 

Cast iron, 

27.000 

7.248 

3080 

2285 

.1205 



A comparison of the 5th and 6th columns de¬ 
monstrates the justness of the preceding remarks, 
making it evident that no relation, such as has 
been conjectured to prevail, exists between the 
specific gravities, tenacities, and fusing points of 

* This alloy was in the state contemplated in this investigation at 
the temperature here noted ; but for a considerable distance below that 
temperature it was in a kind of semi-fluid state, like that of a liquid 
thickened up with some fine grained solid, and appeared to have its 
stationary point, or at least one such point , at about 500°. The original 
investigation of the question relating to stationary points in the cooling 
and solidification of metals and alloys, was made by Rudberg. See 
Annales de Chim. ct de Phys. vol. 48, page 353. Subsequent experi¬ 
menters have, it is believed, added little to his discoveries. 














































































* 


ON THE FUSING POINT OF ZINC, &C. 13 

the metals.* The specific heats and atomic 
weights are annexed in the table to facilitate the 
comparison of these elements with the tenacities; 
but it is believed that on them no satisfactory law 
of tenacities can be founded. In the formula at 
the head of the 6th column, F is the fusing tem¬ 
perature; T, the tenacity, and D the density of 
the metal. The melting point of tin is the stand¬ 
ard of comparison between the proportional num¬ 
bers obtained by the formula. 

< 

# 

\ * 

* This supposed relation was founded on the erroneous measures of 
temperature, formerly applied to determine fusing points. The calcu¬ 
lation of some fusing temperatures on this principle, and a general state¬ 
ment by which to calculate others, is found in the Transactions of the 
American Philosophical Society, Vol. I. New Series, p. 168. The 
paper alluded to was read May 20, 1814. 








EXPERIMENTS 

ON THE 

Adhesion of iron spikes of various forms* 

WHEN DRIVEN INTO DIFFERENT SPECIES OF TIMBER. 

BY PROF. WALTER R. JOHjYSOjX. 

. '\ 

FROM THE JOURNAL OF THE FRANKLIN INSTITUTE. 


In reference to rail-road constructions, bridge building, and several other 
useful applications in civil engineering as well as in naval architecture, the 
adhesion of spikes, bolts, and nails of various forms becomes an object of 
much practical importance. With regard to rail roads this matter is 
worthy of more attention than might at first sight be supposed. Owing to 
the present high price of iron, the fiat rail is often unavoidably adopted in 
preference to the edge rail, and whenever the speed of a train, descending 
by gravity or impelled with great velocity by the moving power, is to be 
suddenly checked by the brake, the friction of the periphery of the wheel 
on the rajl tends to drive the latter lengthwise and thus to force all the 
spikes with which it is fastened, into closer contact with the ends of the 
fibres which have been cut in driving them. If this partial or total drag¬ 
ging of the wheels along the rails takes place, sometimes in one direction, 
and sometimes in the other, the spikes must be subjected to alternate im¬ 
pulses on opposite sides. Indeed, whenever the motive power depends on 
friction for its efficacy, as in the case of the common locomotive engine, 
there is a constant succession of these two opposite dragging forces, the 
engine constantly tending by its driving wheels to urge the rail backward* 
and the train by an equal, but more extensively distributed action, tending 
to urge forward all the rails over which it is, at the same moment, passing. 
So decided is this influence, that on a rail-road where the transportation is 
all in one direction, and where the cars descend by gravity; I have seen 
rails entirely detached, or loosely connected but by a single spike, while others 
clearly indicated by the inclined position of their upper faces or heads, that 
they were pressed into an oblique or leaning position in the wooden sill. 
This single case may serve to show the importance of attending to the 
character of the spikes used in similar constructions. 

To determine some of the points relating to the form of spikes, and the 
kind of timber into which they are driven, the following experiments 
were undertaken; they serve to show the relative economy of each form of 
spike, as well as its absolute fitness for the purpose intended. 

The mode of executing the experiments was to drive each spike to a cer¬ 
tain distance, above its cutting edge, into the edge of a piece of plank or 
scantling, and, by means of a suitable apparatus adapted to that purpose, to 
draw it out by a direct longitudinal strain. The machine employed for 
this purpose was the same as that which has been used for testing the 
strength of iron and copper in experiments on the tenacity of materials 
employed in steam boilers. A strong band or strap of iron connected with 
the weighing beam of that machine held the piece of plank, and a clasped 
pincers with a suitable jaw, for taking hold of the head and projecting part 
of the spike, was attached to the opposite part of the machine, which being 


/ 




2 

tightened by a strong screw, held the spike firmly while the application of 
weights upon the longer arm of the lever drew the timber away and released 
the spike. Care was taken to cause the strain to pass through the axis of the 
spike, and by a very gradual application of weights, to avoid surpassing 
that force which was just sufficient for its extraction. 

The first experiment was upon one of Burden’s patent square spikes 
with a cutting edge, intended to be, in all cases, placed across the grain of 
the timber. This spike was .375 inch square, and was driven into a sound 
plank of seasoned Jersey yellow pine 3| inches. The force required to 
extract it was 2052 lbs. The exact weight of the part driven into the wood 
was 866 grains troy. 

The second trial was upon a flanched, grooved and swelled spike, having 
the grooves between two projecting wings or flanches on the same sides as 
the faces of the cutting edge. The other two sides were 
planes continuing to the head. A cross section of this spike 
taken If inches above its edge or point had the form of the 
x i: x figure annexed* At of an inch from the edge, that i9 


e 

m 


where the flanches project least or where the swell between 
them comes nearest to forming a perfect square,the figure is as follows:—the 
dotted line e e in each figure representing the direction of the cutting edge. 

Towards the head of this spike, the flanching and groov¬ 
ing is suppressed and the form becomes a square. This ex¬ 
periment was made on the same piece of Jersey yellow pine 
as the first, and the weight required for extracting the 
spike was 1596 lbs.; the weight of the part driven in was 
708J grains. The cutting edge was ragged and irregular. The distance 
to which it was driven was 3f inches, as in the first trial. To know the 
relative values of the two forms of spikes we have but to divide the weight 
required for the extraction of each by the number of grains in the part 
which had been buried in the wood. Thus 2052-7-866 = 2.37, and 
1596 -r- 708.25 = 2.112. Hence the plain spike had an advantage over 
the swelled and grooved one in about the proportion 23 to 21. It should 
be mentioned, also, that the plain spike was drawn out by a very gradual 
addition of force; whereas the force of 1596 lbs. drew the grooved spike 
immediately after its application. In the first trial an attempt was made to 
detect any yielding or gradual retreat of the spike before the final start, but 
none w'as perceived. 

The third and fourth experiments were made with the same spikes 
respectively as the first and second; but instead of yellow pine the timber 
employed was thoroughly seasoned white oak. 

The plain spike driven 3§ inches into that timber, required for its extraction 
a force of 3910 lbs., and, as before, exhibited no signs of movement until 
the instant of starting, when it suddenly came out about a quarter of an inch, 
or as far as the range of motion, and the elasticity of the machine would 
permit. 

The flanched, swelled and grooved spike driven 3| inches into another 
part of the same piece of plank, from which the plain one had been extract¬ 
ed, was drawn out with a force of 3791 lbs. A slow motion to the extent 
of or yg- of an inch was in this trial perceived to precede the starting of 
the spike; and was accompanied by a gradual protrusion of the fibres of 
the timber immediately around the iron. 

In these experiments though the plain spike bore the greater absolute 
weight, yet, w hen the weight of metal is considered it is seen that the rela¬ 
tive values of the two are 4.515 in the plain,and 5.354 in the grooved form. 







3 


The various circumstances ot the four preceding experiments are seen at 
a single view in the following table. 


Table I. 


No. of the 
experiment. 

Description 
of spike used 

Kind and 
condition of 
timber. 

Breadth of 

the spike. 

1 

Thickness of 

the spike. 

Depth to 

which it was 

driven. 

Weight in 

grains of the 

part driven 

in. 

Force re¬ 

quired to ex¬ 
tract it in lbs. 
avoirdupois. 

Ratio of the 

extracting 

power to the 

w’ht of spike 

<1> 

ci 

Q 

Remarks. 

1 

Plain 

square 

9pike, 

CBurden’s.) 

Seasoned 
Jersey yel¬ 
low pine. 

inch. 

.375 

inch. 

.375 

inches. 

3.375 

866 

2052 

2.368 

Oct 

27, 

1835 

Force 
gradually 
applied; 
no mo¬ 
tion pre¬ 
vious to 
the start. 

2 

Flanched, 
grooved 
and swelled 

Do. 

.375 

.300 

3.375 

708 

1596 

2.254 

Do. 

Force 
applied; 
at once. 

3 

Burden’s 

plain. 

Seasoned 
white oak. 

.375 

.375 

3.375 

866 

3910 

4.515 

Do. 

Started 

suddenly 

4 

Grooved 

and 

swelled. 

Do. 

.375 

.300 

3.375 

708 

j 

3791 

5.354 

Do. 

1 

Fibres 
protrud¬ 
ed 1-20 
of an 
inch be¬ 
fore the 
spike 
drew out. 


Hence it appears that in yellow pine the grooved and swelled form was 
about five per cent, less advantageous than the plain, while in the seasoned 
oak the former was 18£; per cent, superior to the latter. It is also appar¬ 
ent that the advantage of seasoned oak over seasoned yellow pine for re¬ 
taining spikes is, by a comparison of experiments 1 and 3, as 1 to 1.9; and 
by a comparison of 2 and 4 it is as 1 to 2.37. In the preceding experi¬ 
ments the spikes were driven into the timber and immediately drawn out 
again. In the second series, the spikes were driven into their respective 
pieces of timber and then soaked for a few days in water. The pieces into 
which different spikes were driven, were as nearly alike as it was practicable 
to obtain them, being always cut from the same plank avoiding knots, cracks, 
&c. The following table contains a view of the experiments made after 
soaking the timber. 






































































No. ofthe experi¬ 
ments. 


4 


Table II. 


l 


2 


4 

5 

6 

7 

8 

9 

10 

11 

12 

13 

14 


Timber soaked after Spikes were driven. 


Kind of spike used. 

Kind and condition 
of the timber. 

Breadth ofthe 
spike. 

Thickness of the 

spike. 

--— 

i 

1 Depth to which it 

was driven. 

Weight in grains of 
the part inserted. 

Force to extraet 

the spike in lbs. 

Ratio of extracting 

force to weight of 
spike. 

Date. 

Remarks. 

Swelled 

and 

grooved. 

Chestnut 

unseasoned 

inch. 

.375 

inch. 

.300 

inch. 

3.5 

806 

1710 

2.121 

Dec. 

3, 

1835 

In this and the 
four following 
experiments the 
thickness of the 
spike is that 
found at the bot¬ 
tom or hollows 
of the grooves. 

Do. 

Yellow pine 
seasoned. 

.375 

.300 

3.5 

806 

1668 

2.069 

Do. 


Do. 

Hemlock 

partly 

seasoned. 

.375 

.300 

3.5 

806 

1738 

2.156 

Do. 


Do. 

White oak 
seasoned. 

.375 

.300 

3.5 

806 

3373 

4.184 

Do. 

The oak used in 
this exp’nt was 
firmer than that 
employed in the 
first series. 

Do. 

Locust part 
ly seasoned. 

.375 

.300 

3.5 

806 

4902 

6.081 

Do. 

The timber had 
been slightly 
split by driving. 

With the 
swell filed 
away. 

Unseason¬ 
ed chestnut 

.390 

.300 

3.5 

759 

1352.5 

2.440 

Do. 

The flanches re¬ 
mained after fil¬ 
ing out the swell¬ 
ed part ofthe 
original form. 

Do. 

Seasoned 
vel. pine. 

.390 

.300 

3.5 

759 

1767 

2.328 

Do. 


Do. 

Hemlock 

partly 

seasoned. 

.390 

.300 

3.5 

759 

1296.8 

1.576 

Do. 


Plain spike 
draw filed 
lengthwise. 

Chetnut 

unseasoned 

.400 

.394 

3.625 

933.5 

1790 

1.810 

Do. 


Do. 

Hemlock 

partly 

seasoned. 

.400 

.394 

3.5 

'933.5 

1638.75 

1.755 

Do. 


Do. 

Locust part 
ly seasoned. 

.40C 

.394 

3.5 

933.5 

3990 

4.167 

Do. 


Do. 

Do. 

.400 

.394 

3.5 

933.5 

4332 

4.640 

Do. 

Timber slightly 
split in driving 
the spike. 

Grooved 
&. notched 
or serrated. 

White oak 

.392 

.315 

3.625 

'759 

2622 

3.454 

Do. 


Barden’s 

patent. 

Do. 

.339 

1.328 

3.625 

'639 

12152 

3.367 

Do. 













































































































































































5 


, The first five of the preceding experiments show that with a spike of 
given form, and driven a certain distance into different timbers the order 
tT retentiveness beginning with the highest is, as follows: 1. Locust; 2. 
White Oak; 3. Hemlock; 4. Unseasoned Chestnut; 5. Yellow Pine. 

From the 6th, 7th and 8th experiments, we see that chestnut is still 

above yellow pine, but that hemlock is inferior to both. By the 9th and 

10th, it also appears that hemlock is still to be placed below chestnut. 

Comparing the first experiment in this table with the 6th, and the 2d with 

the 7th, we perceive that the swell towards the point of the grooved spike 

was so far from being an advantage to it, that it, in fact, rendered the 

spike less retentive than when that swelled part had been removed, so that 

even could this form have been produced without any increase in the weight 

of the spike, it w^ould still have been less advantageous than the simple 

groove without the swell, but when it is considered that the swell added 

47 grains (806—759), to the weight, it is evident that the groove alone has 

a decided advantage over the other form. By the trials in unseasoned 

, _ 2440_2121 

chestnut (Nos. 1 and 6) this advantage is 15 per cent, thus--= 15. 

v & 1 2121 

2328_2069 

and by those on yellow pine (Nos. 2 and 7) it is— - ^ --=12.5 per cent. 

In fact, after the ends of the fibres have once been thrust apart by the 
thick part of the swell it is evident that when they come opposite to the 
cavity, above the swell, they must lose some part of their power to press 
the spike and to produce the retaining force of friction. This force must then 
depend for its production on the action of those fibres of the wood which 
are opposite to the swelled portion, or between it and the points of the 
spike. 

In the next series of experiments it was attempted to ascertain the rela¬ 
tion between forms more diversified than had hitherto been employed. 

As it is evident that the total retentiveness of the wood must depend, in 
a considerable degree, upon the number of fibres which are longitudinally 
compressed by the spike, it was inferred that on the area of the two faces 
which, in driving the spike, are placed against the ends of the fibres, must in 
a great measure, depend the retention of the spike. In this series four 
kinds of wood and ten forms of spikes were employed. 

A comparison of the results, given in the following table, will show 
what order these forms would possess among themselves, in point of reten^ 
tiveness as well as the advantages of the respective species of timber into 
which they were severally driven. 




6 


Table III, 

Spikes of various forms—Timber of different kinds. 


No. of the exp’nt. 1 

Kind of spike used. 

Kind and condition 
of the timber used. 

Breadth of spikes. 

Thickness of 

spike. 

Area of two faces. 

• Depth to which 

driven. 

Weight of the part 

inserted. 

Force to extract 

the spike. 

j Ratio of force to 

weight of spike. 

Date. 

Remarks. 

1 



inc. 

inc. 

sq in 

inc. 

gr’s. 

lbs. 


1835 


Straight 

square. 

Chestnut 

unseasoned 

.405 

.402 

2.83 

3.5 

942 

1995 

2.116 

Dec. 

4. 

• 


2 

3 

4 

5 

Burden’s 

patent. 

Do. 

.373 

.384 

2.64 

3.5 

866 

1873 

2.162 

Dec. 

8. 


Broad flat. 

Do. 

.539 

.288 

.377 

3.5 

3.5 

3.5 

898 

2394 

2.663 

Bee. 

4. 


Narrow flat. 

Do. 

.390 

.253 

2.73 

566 

2223 

3.927 

Dec. 

8. 


Straight 

square. 

White oak 
thoroughly 
seasoned. 

.405 

.402 

2.83 

942 

3990 

4129 

Dec. 

7. 


6 

Broad flat. 

Do. 

.539 

.288 

3.77 

3.5 

898 

5130 

5.’712 

Do. 


7 

Narrow flat. 

Do. 

.390 

.253 

2.73 

3.5 

566 

3990 

7.049 

Do- 

/ 

8 

9 

Burden’s 

patent. 

Do. 

.373 

.384 

2.64 

3.5 

866 

3905 

4.509 

Do. 

* 

Cylindrical 
with cut¬ 
ting edge. 

Do. 

diam 

.485 



3.5 

1211 

3876 

3.200 

Do. 


10 

11 

Grooved 

and 

swelled. 

Do. 

.375 

.375 

2.60 

3.5 

806 

3727 

4.624 

Do. 

The measures in 
this and the two fol¬ 
lowing cases, taken 
outside of flanches. 

Grooved 
but not 
swelled. 

Do. 

.375 

.375 

2.60 

3.5 

759 

4247 

5.662 

Do. 


12 

Grooved 
and bot¬ 
toms of 
grooves 
serrated. 

Do. 

.375 

.375 

2.60 

2.5 

500 

2650 

5 300 

Do. 

The weight of part 
inserted is given by 
estimation in this 
experiment. 

13 

Square. 

Locust sea¬ 
soned for 3 
years. 

.405 

.402 

2.83 

3.5 

942 

5967 

6.334 

Dec. 

8. 


14 

Broad flat. 

Do. 

.539 

.288 

3.77 

3.5 

898 

7040 

7.839 

Do. 


15 

Narrow flat. 

Do. 

.390 

.253 

2.73 

3.5 

566 

5273 

9.316 

Do. 



























































































































































































7 


Table III.—(Continued.} 


1 No. ofthe exp’nt. 

Kind of spike used. 

Kind and condition 
of the timber used. 

Breadth of spikes. 

| Thickness of spike. 

Area of two faces. 

Depth to which 
driven. 

Weight of the part 

inserted. 

Force to extract 

the spike. 

1 Ratio of force to 

weight of spike- 

i 

Date 

Remarks. 




inc. 

inc. 

sq in 

inc. 

gr’s. 

lbs. 


1836 


16 

Cylindrical 
pointed 
with 15 
grooves 
tiled longi¬ 
tudinally 
from the 
points up¬ 
ward. 

Ash season¬ 
ed. 

diam 

.500 



3 5 

929 

2052 

2.208 

Jan. 

4. 

In this and the two 
following exp’nts 
the spikes were 
driven into the tim¬ 
ber in the direction 
of the length of the 
fibres. 




diam 









17 

Do. 

Do. 

.500 



3.5 

929 

2309 

2.507 

Do. 


18 

Plain cylin- 

Do. 








Do. 



drical poin- 












ted, scale 


diam 










not rem’d. 


.500 



3.5 

1015 

2451 

2.414 




The above table furnishes three sets of comparisons for deducing the 
relative retentive powers of green chestnut, thoroughly seasoned oak, and 
equally seasoned locust. Thus the weight, which in those three cases 
drew the square spike from chestnut, was 1995 lbs. That which extracted 
the brood flat one, 2394, and that which drew the narrow flat one from the 
same timber, was 2223. The sum of these is 6612. The sum of the three 
numbers for the same three spikes used with oak, was, by experiments 5, 
6, and 7, 13110; and the same of the three in locust, by experiments 13, 
14, and 15 is 18280, these three numbers have to each other the relation 
of 1, 2, and 2f, from which we infer that oak is almost precisely twice , and 
locust 2f times as tenacious as unseasoned chestnut. By comparing to¬ 
gether the results of experiments 1 and 2, it will be seen that the weights 
required for extracting the two spikes respectively are more nearly propor¬ 
tional to the breadths than to either the thicknesses or the weights of the 
spikes, for the spike with a breadth of .405 inch, and a thickness of .402 
required 1995 lbs. for its removal, while that which had a breadth of .375 
inch, took 1873 lbs. 

Now .373 : .405 : : 1873 : 2033 for the calculated retentiveness, in¬ 
stead of 1995 as given by experiment,—a difference of only -f 38 lbs. be¬ 
tween the observed and calculated results. Calculating the retention by 
the iveights of the respective spikes, we should have 866 : 942 : : 1873 : 
2037, or a difference of 42 lbs; while using the thicknesses alone, we obtain 
.384 . 402 : : 1873 : 1960, a difference of an opposite kind of 35 lbs. from 
the observed result. The greater thickness yielding the less retentive 
power. This correspondence between the breadths and the extracting 
weights, becomes still more apparent when we compare the third and espe¬ 
cially the fourth with the second experiment. Thus for the broad flat spike 
(3d experiment) compared with experiment 2nd we have, 

































































By breadths .373 : .539 : : 1873 : 2701 instead of 2394—diff. + 307 
By weights .866 : .898 :: 1873 : 1942 - - “ — 452 

By thicknesses .384 : .288 : : 1873 : 1379 - “ — 1015 . 

And for the thinner and lighter spike (experiment 5th) compared with 
No. 2. we have, 

By breadths .373 : .390 : : 1873 : 1958 instead of 2223 observed, dif — 265 
By weights .866 : .566 : : 1873 : 1224 - - “ —999 

By thickness .384 : .253 :: 1873 : 1234 - - _ “ — 989 

Nearly the same conclusions would result from a comparison ot those 
trials which were made on seasoned white oak and locust. Indeed it ap¬ 
pears, that with a given breadth on the face of the spike, a diminution ot 
thickness is sometimes a positive advantage to the retentiveness ot the tim¬ 
ber, for on white oak the spike which had a breadth of only .390, required 
as much force to extract it, as one of which the breadth was .405—though 
the thickness of the former was but .253, while that of the latter was .402, 
and on chestnut the thinner, narrower and lighter spike required absolute¬ 
ly more force to withdraw ir, than the other. This leads us to notice the 
different kinds of action of the respective spikes on timbers of various kinds. 

In the softer and more spongy kinds of wood the fibres instead of being 
forced back longitudinally and condensed upon themselves, are by driving 
a thick, and especially a rather obtusely pointed, spike, folded in masses 
backward and downward so as to leave, in certain parts only, the faces of 
the grain of the timber, in contact with the surface of the metal. 

That the view just presented is correct, seems also probable from what 
was observed in the case of the swelled spike. For while the grooved but 
unswelled one. driven into chestnut timber (Table II. Ex. 6,) required 1852 
lbs. to extract it, the grooved and swelled one (Ex. 1. same table.) took but 
1710. Anti in table III. Ex. 2, we find the swelled spike drawn from 
white oak by 3727 lbs., anti the grooved but not swelled one (Ex. 12,) re¬ 
quiring 4247. Hence, it appears to be necessary in order to obtain the 
greatest effect, that the fibres of the wood should press the faces as nearly as 
possible in their longitudinal direction, and with equal intensities through¬ 
out the whole length of the spike. 

Arranging the spikes according to the order of their ratios of retention to 
Weight , as given by the experiments from 5 to 12, inclusive, in Table III. # 
We have the following: 

^ _ o 


1. 

Narrow fiat, with a ratio of 

7.049 

Q 

Wide flat, 

. 

5.712 

3* 

Grooved but not swelled, 

-• 

5.662 

4. 

Grooved and notched, 

- 

5.300 

5. 

Grooved and swelled, 

- 

4.624 

6. 

Burden’s patent, 

- 

4.509 

7. 

Square hammered spike, 

- 

4.129 

8. 

Plain cylindrical, - 

- 

3.200 


Experiments 16, 17, and 18 of the same table were made by driving the 
spikes, which were cylindrical with conical points into the timber endwise 
of the grain. This method of comparing two forms, the one grooved, and 
the other plain, was adopted on account of the extreme liability of the tim¬ 
ber to be split by driving spikes of these forms across the direction of the 
fibres. It was observed that on drawing these spikes the holes were almost 
perfectly square. This resulted from the position of the rings of annual 
growth, and the greater elasticity in some directions than in others. It 
is probable that, it the filed grooves,in experiments 16 and 17, had been 


9 


covered with a scale of oxide, as was the case with the plain spike used in 
experiment 18, the former would have given a somewhat higher result. 
When holes are drilled into stone blocks and afterwards plugged with tim¬ 
ber to receive spikes, in fastening on the chairs of edge rails, the method 
of experimenting just described finds an application, and it is probable that 
in such cases the grooved cylinder, with a conical grooved point, may prove 
advantageous. 

. A few experiments were made to determine the effect of driving spikes to 
different depths on the total amount of retention. For this purpose two 
different spikes were selected, viz: the square hand-wrought spike, the sec¬ 
tion of which was .405 X .402, and the wide flat one, of which the section 
was .539 X :288. They were respectively driven to a certain depth into 
unseasoned chestnut—and then subjected to force just sufficient to start 
them,—this force was noted, the spike was then driven another inch and 
the force applied in like manner. All my experiments proved that when a 
spike is once started, the force required for its.final extraction is much less 
than that which produced the first movement. This is readily accounted 
for, on the principle that a wedge shaped point was from half an inch to an 
inch in length, and as this on the starting back of the spike a very little 
distance, became mostly relieved from the pressure of the fibres, all that 
part of the retention, which had been due to the wedged shape portion was 
at once destroyed. The following table will show that the mere starting of 
the spike, with parallel faces, does not essentially diminish the retention 
when again driven into the timber to a greater depth than before. 

But when a bar of iron is spiked upon wood, if the spike be driven down 
until the bar compresses the wood to a great degree, the recoil of the latter 
may become so great as to start back the spike a short distance after the 
last blow has been given. In this case a great diminution in the useful 
effect will be the consequence. This shows that a limit may exist to the 
force which we should apply in urging down spikes or bolts, especially 
those with large heads, destined to fasten materials together. 

Table IV. 


Spikes driven to different depths. 


&o. of experiment. 

Form of spike. 

Kind and condition 
of timber. 

Breadth of Spike. 

Thickness of spike 

Area of the faces. 

| Depth to which the 

1 spike was driven. 

Weight of the part 
inserted- 

; Force to extract 

the spike. 

Ratio of force to 
weight of spike. 

Date. 

I Remarks. 




in. 

n. 

sq. in. 

in. 

grs. 

lbs. 


1835 



1 

Square not 

Chestnut 








Dec. 

Retention 


filed. 

unseasoned. 

.405 

.402 

.7695 

1.9 

483 

1183 

2.428 

4. 

area of faces 

i 2 

Do. 

Do. 

Do. 

Do. 

1.1745 

2.9 

789 

1995 

2.528 

Do. 

Do. 

=850 

o 

O 

Do. 

Do. 

Do. 

Do. 

.1579 

3.9 

1095 

2565 

2.342 

Do. 

Do. 

=795 

4 

Broad flat. 

Do. 

. 9 

.288 

.9702 

1.8 

442 

1525 

3.457 

Do. 

Do. 

=785 

5 

Do. 

Do. 

Do. 

Do. 

1.5092 

2.8 

745 

2594 

3.482 

Do. 

Do. 

=865 












Mean 813 


B 






























10 


By comparing experiments 1 and 4 together it will be found that weight 
for weight, the flat spike had, when driven 1.8 inches, an advantage of 
42.5 per cent, over the square one; and by like comparison of experiments 
2 and 5, it is evident the former had a superiority of 37.7 per cent. As 
the spike when driven in only 1.9 inches had a much less proportion of its 
parallel faces and a greater proportion of the wedge shaped point, ex¬ 
posed to the reaction of the fibres, it is reasonable to expect that the re¬ 
tention would not correspond precisely with the lengths inserted. It will 
be understood that when we speak of cutting edges and the wedge shaped 
portion of spikes, whether square, flat, or cylindrical, the direction of the 
cutting edges is always across the fibre or grain of the timber. It must be 
evident that the wedge shaped part may be so acute as to correspond nearly 
with two parallel faces, in which case, the tendency to retreat from the 
lateral pressures is small, and the pressures themselves increasing from the 
point upwards to where the spike is thickest, the total efficiency of a given 
length may be as great as that of an equal length of the parallel faces, and 
even greater provided the thickness of the spike be so great as in driving 
it to produce much crushing and irregular folding of the fibres of the tim¬ 
ber. If, on the contrary, the edge be very blunt, the tendency to recoil 
may be such as to diminish the adhesion and in this case the effect of the 
wedge shape is negative. In the other it may be positive.* The 1st, 2d, 
and Sd experiments indicate, in the 10th column of the preceding table, that 
beyond a certain limit the ratio of weight of metal to extracting force 
begins to diminish, showing that it would be more economical to increase 
the number rather that the length of spikes for producing a given effect in 
fastening materials together. In this case also it will be perceived that 
the adhesion has a much closer relation to the areas of the compressing 
, faces of the spikes than to their weights. The 12th column shows that for 
three of the experiments this ratio may be regarded as identical , and the 
whole set goes to prove that the absolute retaining power of unseasoned 
chestnut on square or flat spikes of from two to four inches in length, is a 
little more than 800 lbs. for every square inch of their two faces which 
condense longitudinally the fibres of the timber. 

The accompanying figures represent the appearances of timber as de¬ 
veloped by splitting the specimens, through the axis of the cavities, left by 
the spikes when withdrawn. 

Fig. 1—Is that presented by the locust timber, mentioned in Table II., 
Experiment 11, in which the weight required to extract the spike was 3990 
lbs. The upper part of the figure exhibits the rising up of the timber just 
as the spike starts. In every case this effect was found, on examining the 
timber, to have been of very limited extent. 

Fig. 2—Represents the grain of chestnut timber as affected in experi¬ 
ment 3, Table III, with the broad flat spike, and other trials. At the point 
of inflection downward the grain appears to be not only bent but often actu¬ 
ally broken oft'. 

Fig. 3—Exhibits the appearance of a specimen of hemlock timber, used 
in experiment with the straight grooved spike, (Fig. 4 of spikes) in which 
the weight required to extract it was but 1296 lbs.—See Table II, Experi¬ 
ment 8th. 

* The following formula may represent the several experiments R=// r +c in which 
R is the observed retention; /= the length in inches of the part inserted;/= the force 
of retention on one inch of the parallel sides; and c= the difference between the re¬ 
tention of a parallel portion of the spike and of an equal length of the converging faces 
near the point. The sign of ambiguity is due to the cause above stated. 


11 


1 * 2 . Figures of Timber. 3. 4. 



Fig. 4—Conveys an idea of the manner in which a defective specimen 
of pitch pine was affected by a spike. The force required to draw this 
spike was so trifling that it was not thought worth recording in the tables. 


Figures of Spikes. 



Fig. 1—is a square spike .405 of an inch wide on each face,'—referred 
to in Table III, Experiments 1, 5, and 13. 

Fig. 2—is a cylindrical spike .485 inch in diameter, sharpened to a cut¬ 
ting edge—see Table III, Experiment 9. 

Fig. 3—is the grooved and notched spike, serrated in the bottoms of the 
grooves on the two faces, Table III, Experiment 12. 

Fig. 4—is a spike with plain grooves on the faces, extending from the 
upper part of the bevel to the height of about 3| inches. 

Fig. 5—is a grooved and swelled spike, that is, having the groove deeper 
at the distance of two inches from the point, than it is at one inch from it. 
At the former the depth of each groove is .066 inch. 

Fig. 6—is a cylindrical spike .5 inch in diameter, tapered to a point. 

Fig. 7—is a spike of the same diameter as the preceding, but having 15 
spiral grooves proceeding from the point upward. 

Fig. 8—is a flat spike .390 inch in breadth, and .253 inch in thickness. 
See Table III, Experiments 4, 7, and 15. 

Note.—T he only series of experiments, analogous to those above detailed, 
which has fallen under the notice of the writer was made in 1824*, by Mr. B. 

* See Gill’s Technical Repository, vol. V., p. 248. 


















































































































































12 


Bevan, on the adhesion of sprigs, brads and nails, when driven into timber 
longitudinally and transversely. His operations were extended to several 
kinds of timber, viz:—Norway deal, dry oak, elm, dry beech and green 
sycamore. 

He employed some nails of a very minute size of which 4560 were re¬ 
quired to make a pound avoirdupois. One of these required 22 lbs. to ex¬ 
tract it, when driven .4 of an inch into pine board. From this size he 
advanced by several gradations to the sixpenny wrought nail, of which 73 
make a pound avoirdupois. Of the latter he drove one to the depth of one 
inch successively into pine, elm, dry oak, dry beech, and green sycamore, 
and found the forces required for its extraction to be as follows: 

For Pine, 187 lbs. Beech, 667 

Elm, 327 Sycamore, 312 

Oak, 507 

Mr. Bevan examined, to some extent, the difference between driving a 
nail by percussion with a hammer of known weight and range of fall, and 
forcing it into the wood by simple pressure. This curious inquiry did not, 
for obvious reasons, enter into the plan of the writer of this article. Mr. B. 
found that to force a sixpenny nail into pine 1 inch, it took a pressure of 
235 lbs.^ to extract it, 187; to force it in 1£ inch 400; to extract it 327; 

“ 2 inches 610; “ 530. 



Observations on the effects of a remarkable at¬ 
mospheric current or Storm as witnessed on 
the day following its occurrence. By Walter 
R. Johnson, A. M., Mem. Acad. Nat. Sci. of 

tr 

Philadelphia, &c. 

Read Febuary, 21, 1837.* 

Considered as a meteorological phenomenon, 
the calamity which, on the 19th of June 1835, 
desolated a part of the city of New-Brunswick 

* The substance of these observations was verbally communicated to 
the Academy, June 23d, 1835—together with a diagram explanatory of 
the positions of trees prostrated, materials strewed upon the ground, and 
the situation of buildings, removed towards the centre of the track of the 
storm. The writer then took occasion to suggest that an examination 
of the forest land, passed over by the tornado, should be made by the 
help of the compass, in order to verify the justness of the views which 
he had presented, respecting the direction of the trees in different parts 
throughout the breadth of the track. This task was subsequently perform¬ 
ed during a visit to the scene of devastation, by Messrs. Espy and Bache, 
the result of which showed conclusively the correctness of the general 
statements contained in this paper. The remarks in this article were 
prepared immediately after the communication to the Academy, and sub¬ 
mitted to a friend, in whose hands they remained till within a few days 
of the time when they were read; which accounts for the delay in their 
presentation to the Academy, and has given time for the publication of 
several other accounts, the materials for which were afterwards collected. 


o 


OBSERVATIONS ON A REMARKABLE 


in New-Jersey, is worthy of the most attentive 
investigation. In connexion with the accompany¬ 
ing sudden, and singular changes of temperature, 
and moisture in the air, it may serve to illustrate 
the causes of those occurrences which, sometimes 
in our own climate—and more frequently in tro¬ 
pical regions—display effects which have hitherto 
perplexed the minds of the most acute observers. 
All accounts concur in representing the air of the 
morning, and indeed of the whole day up to the 
time of the tornado, as unusually sultry. This 
was observed between the hours of two and four 
P. M., in a ride from Hightstown to Princeton, 
a distance of about nine miles ; also, in the 
city of New-York, and on the voyage from the 
latter city to New-Brunswick. At four o’clock 
the sun was still unobscured at Princeton; but 
within half an hour a cloud from the north-west 
had reached that place, and a shower of rain, 
accompanied by a brisk wind from the south-west, 
had commenced. Before five o’clock, the rain 
had ceased, and the air was less oppressive. The 
evening continued tranquil until ten o’clock, when 
another shower of rain fell, accompanied by some 
wind; but within half an hour, the sky was once 
more cloud less, and the wind began to rise with 
much force, from the west or north-west. Some 
observations on Polaris, Saturn, and other hea- 



ATMOSPHERIC CURRENT. 


3 


venly bodies, were made by Mr. Alexander of 
that place, between eleven and twelve o’clock, 
but the state of the air did not appear favourable 
to the distinct, and steady perception of the mi¬ 
nuter telescopic objects; owing, as was supposed, 
to irregular refraction, and the occasional sudden 
formation of mist in certain quarters of the hea¬ 
vens. A sensible depression of the dew-point was 
noticed at the time as indicated by the action of the 
air on the lungs, as well as on the surface of the 
body. From 12 at night to 5 the next morning 
the wind was boisterous; and a great change in 
the state of the atmosphere had obviously taken 
place. An electrical machine, which it had on the 
day previous been found impossible to excite, was, 
at nine or ten o’clock, A. M., able to yield 
sparks an inch and a half or two inches long, be¬ 
tween balls three-fourths of an inch in diameter— 
a sure indication of an increased distance between 
the dew-point and the temperature. 

Intelligence of the occurrences at New-Bruns- 
wick having been received during the forenoon, it 
was resolved to visit the spot, and endeavour to 
ascertain, by observation and inquiry, while the 
traces were yet unobliterated, such facts as might 
explain the mode of action by which the devasta¬ 
tion had been effected. On arriving within six 
miles of New-Brunswick, on the old turnpike 


4 


OBSERVATIONS ON A REMARKABLE 


road, we* were informed by an eye-witness, that 
it had been seen about a mile and a half north¬ 
easterly from that point; and that the dense black 
cloud was, by the junior observers, conceived to be 
filled with crows , — an appearance, afterwards 
explained by the fact that shingles, boards, &c., 
had been carried upward by the tempest from 
buildings destroyed in that vicinity. 

On reaching the height of land, at about half a 
mile from the dense portion of the city, the first 
buildings which had been damaged by the tornado 
were passed. A barn had been completely de¬ 
molished, and most of the lighter materials scat¬ 
tered to a great distance. The house was not 
thrown down, but left leaning with no part of the 
roof remaining, except some of the rafters; and 
the fact here witnessed was repeatedly observed 
in the town below, where several houses within 
the path of the tornado were deprived of their 
shingles, and the ribs which had held them to the 
rafters; but the latter still continued partially or 
entirely undisturbed. In a few cases, in which 
the ridge of a building lay in a northerly and 
southerly position, the eastern slope of roof was 

* In this excursion, and the subsequent inquiries, the writer was 
accompanied, and aided by his friend Professor Joseph Henry; who 
is to be considered as entitled to a full share of whatever credit may 
attach to the observations referred to in this paper. 


ATMOSPHERIC CURRENT. 


5 


observed to be removed, or at least stripped of its 
shingles, while the western slope remained entire. 
Many buildings were likewise observed with 
holes in their roofs, whether shingled or tiled, but 
otherwise not much damaged, unless by the demo¬ 
lition of windows. These appearances clearly 
demonstrated the strong upward tendency of the 
forces by which they were produced, while the 
half unroofed houses, already mentioned, prove 
that the resultant of all the forces in action at the 
moment was not in a perpendicular to the horizon, 
but inclined to the east. Such a force would ap¬ 
ply to the western slope of the roof some counter¬ 
acting tendency, or relieve it from some portion 
of the upward pressure. Had there been no other 
facts to show the powerful rushing of currents up¬ 
ward, the above would, it is conceived, have been 
sufficient to settle the question, but taken in con¬ 
nexion with the circumstance that roofs so removed, 
were carried to a great height and their fragments 
distributed over a large extent along the subsequent 
path of the storm, that beds and other furniture were 
taken out of the upper stories of unroofed houses, 
that persons were lifted from their feet or dashed 
upward against walls; and that in one instance, 
a lad of eight or nine years old, was carried up¬ 
ward and onward with the wind, a distance 
of several hundred yards; and particularly that 


6 


OBSERVATIONS ON A REMARKABLE 


he afterwards descended in safety, being pre¬ 
vented from a violent fall by the upward forces, 
within the range of which he still continued :—in 
connexion with these and similar facts, it seems 
impossible to doubt that the greatest violence of 
action was in an upward and easterly direction. 

The next point to which attention was called by 
the appearances around, was the manner in which 
this upward current had been supplied from below; 
and for the solution of this question, it was neces¬ 
sary to compare objects throughout the whole 
breadth of the track left by the storm. A peach 
orchard on the slope of the hill descending to the 
town gave the first indication in regard to this 
matter, but the larger fruit and ornamental trees, 
in the gardens of Dr. Jane way, Messrs. 
Kikpatrick and others, in the same neighbour¬ 
hood, together with an inspection of the forest on 
the east side of the river, showed conclusively that 
on the extreme borders of the track the forces 
were nearly, or quite at right angles to its gene¬ 
ral direction. Uprooted trees along the southern 
border lay with their tops towards the north; those 
on the northern border to the south, thus point¬ 
ing to a common object in the central line of the 
current. From the outer edges however toward 
this central line the trees were observed on both 
sides to have a gradually increasing inclination to- 


ATMOSPHERIC CURRENT. 


7 


wards the east, and in the middle to be entirely 
in that , as a general direction. I do not recollect 
to have encountered a single case in which the 
top of a tree ivith its roots in the ground was 
lying towards the west, though I cannot say that 
none occurred, for among the houses and other 
obstacles within the city, presenting different de¬ 
grees of resistance to the lateral currents, there 
may very probably he some points in which great 
violence was exerted in directions varying from 
the general course of action. None were seen 
with the tops from the centre of the path. Ano¬ 
ther fact to this point, is, that Dr. Janeway’s 
barn, a frame building, which was on the south- 
rely part of the track, was unroofed, and the re¬ 
maining part of the structure with its contents 
removed bodily three or four feet to the north¬ 
ward. All the herbage, shrubs and trees in its 
immediate vicinity, and the trees of K IRKPAT- 
rick’s garden, were found lying with their heads 
in a northerly or northeasterly direction. Simi¬ 
lar to the case of the barn just mentioned was 
that of Bishop’s store, near the rivet; which, 
standing on the northern border, had been lifted 
from its foundation about four or five feet towards 
the south. A row of poplar trees which had 
been prostrated in the lower part of the city, 


3 OBSERVATIONS ON A REMARKABLE 

and on the northern part of the path was observed 
as a striking exemplification of the application of 
lateral force, every tree taking in its fall a south¬ 
erly direction. Another evidence of lateral 
inward currents, was found in the appearance of 
many forest trees, east of the river, which though 
too far removed from the central line of the 
path to be uprooted, were still so much within the 
range of the lateral forces as to have their outside 
limbs, or those most remote from the central line,' 
broken off by the effect of cross strain; while no 
similar fracture was seen on limbs turned towards 
the centre of the path. This result will be easily 
understood, when we consider the well known 
difference between breaking a limb by cross strain 
and that of drawing it asunder by simple longi¬ 
tudinal tension. 

Another fact indicative of the direction of cur¬ 
rents from the sides inward, was noticed on the 
plain east of the Raritan, where the fragments of 
boards, shingles, ribs, &c., which had been 
brought from houses demolished in the city, were 
seen to be arranged on the ground with some 
irregularity, certainly, but with far greater con¬ 
formity of position than we could have anticipated. 
Their longitudinal direction was generally towards 
the central line, and also towards the point to 


ATMOSPHERIC CURRENT. 


9 


which the storm was moving. Many of these 
were found far beyond the belt of ground on which 
the violence of the wind had been exerted. Their 
position may be explained by referring to the 
three forces in action at the moment they reached 
the ground:—first, the force of gravity, which, if 
the air had been motionless, and the bodies de¬ 
scending perpendicularly, would probably—from 
the unequal density of the parts of the several 
masses—have caused most of them to descend 
endwise; and then the position, subsequently 
taken by them respectively, would have been a 
matter of indifference, and we might have expected 
to find them lying promiscuously. But, second, 
they were, while in the air, moving onward with the 
storm in an easterly direction and when the lower 
end struck the ground, the composition of this force 
with gravity, would naturally have thrown the 
centre of gravity over to the east, and we should 
have expected to find the lighter end of every piece 
of timber in that direction. But, third, if a cur¬ 
rent of wind were encountered near the ground, 
running towards the centre of the path, we should, 
on the north side of the path, expect to find the 
lighter ends of each piece directed to the south¬ 
east, and on the south side, to the northeast; 
precisely what appeared to be the case, so far as 


10 OBSERVATIONS ON A REMARKABLE 

could be judged from the general appearance of 
the masses. 

The next set of facts observed, was that which 
relates to the course of the materials projected 
upwards after they had arrived at a considerable 
elevation. All accounts agree that the appearance 
of the cloud was that of a funnel or inverted cone 
with the apex resting on the ground. The falling 
rafters, scantlings, and other parts of the ruined 
buildings, generally indicated that they were, 
subsequently to the upward violent action, carried 
outward by the gradual enlargement of the current 
into which they had been drawn. The shingles 
and boards, just described, were cases in point 
being found far beyond the trail of the tornado 
as marked upon the surface. Rafters, which 
penetrated buildings south of the track, entered 
them on the north side and in a direction inclining 
to the southeast. Their descent in some instances 
was with great violence, contrary to what hap¬ 
pened in the range of the upward motions; where 
a lad, already referred to, was deposited in safety 
after an aerial journey of one-fourth of a mile. A 
window frame and brick wall were, in one in¬ 
stance, penetrated by a rafter, twenty feet in length, 
eight inches wide, and from four to six inches 
thick. In the passage of the storm from the city 


ATMOSPHERIC CURRENT. 


11 


to the opposite bank of the Raritan, no indications 
are, of course, left to mark the peculiar action 
upon the waters; though we have heard it stated, 
but cannot say upon what authority, that the bed 
of the channel was laid bare, and from the nature 
of the forces and their violence, we cannot doubt 
that had it traversed a great extent of water sur¬ 
face, it would have assumed the character, as it 
certainly had the form , of a water spout. On 
encountering, however, the opposite bank, some 
peculiar effects were seen to have been produced. 
The upper edge of the bank especially, was mark¬ 
ed by two well defined stripes, each from ten to 
twenty feet wide, and one hundred, or more, feet 
asunder. Here, it was supposed, must have 
been the outer edge of the aerial trunk, or funnel 
through which the air rushed upwards, and as the 
tornado, in its onward movement, advanced against 
the bank, the air coming in on every side to fill 
up the partial vacuum would exert the greatest 
force at the moment when it changed its horizontal 
for a vertical motion. The surface of the ground 
beyond this point seemed, in some places, to have 
been raised, as if the air beneath, by its sudden 
rarefaction, had thrown up small portions of the 
soil which was rather dry and porous; and it is, 
perhaps, worth consideration, whether this cause 


12 OBSERVATIONS ON A REMARKABLE 

may not, in this and similar occurrences, have 
facilitated the overturning of trees themselves. 

Jt was a subject of regret at the moment, that 
want of time, and of a suitable instrument to 
measure the exact course of the tornado, and the 
precise position of trees in the different parts of 
the track, prevented carrying out a plan, which 
suggested itself on the spot, as the most satisfac¬ 
tory method of arriving at precision on those 
points. 

In conclusion it may he remarked, that the 
directions and intensities of the forces in this 
occurrence, together with the hygrometric states of 
the air, preceding and following the meteor, and 
the inverted conical form of the moving column, 
as confirmed by several witnesses, not less than 
the fall of hail, and the distribution of fragments 
of materials beyond the path of the ground current 
— seem most satisfactorily accounted for, on the 
supposition that a disturbance of atmospheric 
equilibrium, results from a deposition of moisture 
in the higher regions of the atmosphere giving 
out a great amount of latent heat, which, in turn, 
expands the cold dry air above the forming cloud, 
and creates an ascending movement; the expansion 
of pure air by an addition of heat, being in such 
cases much greater than the contraction of the 


ATMOSPHERIC CURRENT. 


13 


atmospheric mixture by a condensation of its 
moisture.—In this effect is, of course, involved the 
well known principle that the capacity of air for 
heat is augmented as its volume expands, but the 
increase of capacity for heat being less rapid than 
the supply of heat from aqueous depositions, an 
ascending current is maintained with a force due 
to the difference of these two causes. * 

* The origin of this view of the subject with which the writer had 
been made acquainted previously to the examination above detailed, is 
due to Mr. J. P. Espy. 











t • 

























t 










SCHOOLS OF THE ARTS. 


R- 

BY W. JOHNSON. 

A /, 


DELIVERED BEFORE THE 


AMERICAN INSTITUTE OF INSTRUCTION, 


AT ITS ANNUAL MEETING. 


BOSTON, AUGUST, 1835. 
















Among numerous causes which contribute to the welfare 
of our species, considered in the aggregate, few can be 
mentioned more deeply interesting, than the productive 
industry of nations. 

While war was the chief occupation, and rapine the fre¬ 
quent amusement of those who boasted themselves the 
chiefs of mankind, jt can hardly be considered surprising 
that the industrious, of all classes, should be little regarded, 
or if heeded at all should be mainly employed as the servile 
ministers to pride, avarice, lust or ambition. 

It was not until the course of events had in some meas¬ 
ure opened the eyes of mankind to the folly of attributing 
to martial exploits all the glory which human beings can 
possibly attain, to the glowing absurdity of investing the 
mere soldier of fortune with supreme control over the lives 
and the destinies of his fellow beings, and to the monstrous 
injustice of placing those who essentially support and 
adorn society, in a degraded rank with respect to the other 
classes of their fellow men ; — it was not until these truths 
had gained some ascendency over the prejudices of the 
world, that it began to be a matter of grave deliberation, 
how the interests of the industrious classes could be ef¬ 
fectually served ; — how the tiller of the soil, the tenant of 
the workshop, and the traverser of the ocean, could be 
secured, each in the possession of those fruits of his labors, 
which, all confessed, were most richly merited. 

It is true that long before any such estimate of the value 
of industry had been distinctly avowed, and long before 
the science of political economy had assumed a rank 

2 



4 


MR JOHNSON’S LECTURE. 


among her sisters, there was an abundance of legislative 
enactments, or of arbitrary edicts, touching the industrious 
callings. But these were commonly designed to promote 
the temporary aims of governments, and would never have 
been enacted for the mere purpose of advancing the hap¬ 
piness of the artizan as an important member of the body 
politic. 

Nor would the convenience, the interest, or the wishes, 
of a great majority of a nation have proved an adequate 
motive to induce the rulers of past generations to encour¬ 
age the labors of industry. 

The question with them was, how can the sinews of 
war, and the means of regal aggrandizement be most plau¬ 
sibly and with the least resistance, extracted from the hands 
of industry and thrust into the royal coffers? 

Each monarch, and each of his ministers, answered the 
question according to the dictates of his own ingenuity, 
subtilty, wants or fears ; and hence the diversity of schemes 
and measures for raising revenue or for securing adherents 
among the useful classes; — useful according to the 
political use which could be made of them. The arti¬ 
zan was accordingly subjected to perpetual fluctuations 
in the condition and circumstances of his life; — 
today, courted, flattered and patronized, — tomorrow, 
neglected, contemned and oppressed with exactions. 
Now, invited to quit the land of his nativity in order to 
enjoy more of the sunshine of royal favor in a foreign 
realm — then by the operation of tyrannical edicts com¬ 
pelled to abandon his home and seek an asylum among 
strangers, to create perchance after years of privation, a 
new demand for the products of his skill. 

But these things have given place within the last cen¬ 
tury to a state of affairs far more propitious to the general 
interests of society, more grateful to the feelings of the 
industrious, and more strictly in accordance with the nat¬ 
ural sense of justice than any which had preceded. 

Wherever civilization prevails, — wherever the popular 
mind has freed itself from the bonds of prejudice, there we 
shall find the importance and the activity of the arts daily 
increasing. 

Checked, perhaps, and occasionally paralyzed by the ig¬ 
norance of those who affect to be their guardians or by 


SCHOOLS OF THE ARTS. 


5 


the obstinacy of those who refuse their just claims to re¬ 
spect, still their vigor is unabated —their march firm and 
ever onward. 

Divided and distracted on other questions, — pouring 
out, perchance, anathemas on each other’s political or reli¬ 
gious opinions,— men still very generally agree to adopt 
and to continue the use of all the substantial physical con¬ 
veniences of which science, art and fortune will enable 
each to avail himself. And we need not go far to search 
for the cause of this unanimity. Every individual has the 
same reason for it, and he can state his reason in five 
words, — “I prefer comfort to discomfort .” 

But what evidence have we, that the prevalent activity 
in the arts has really improved the human condition? 

To furnish a perfectly unexceptionable reply to this in¬ 
quiry it would be necessary to enter into a detailed com¬ 
parison of the circumstances under which various classes 
of society have in different ages been found existing ; to 
show how, they are now relatively above the condition of 
their ancestors and how many of the superior incidents of 
their present state are due to the modern advancements 
in useful arts. We may venture to predict, that such an 
investigation would end in a conviction, that the private 
citizen, possessing a tolerable competency in our day, has 
at his command infinitely more of the truly good things of 
life, than could possibly have been procured by the nobles 
and dignitaries of other days. 

Take into view the food, the clothing, the habitations of 
men ; the healthiness, the longevity, the intelligence of 
whole communities; witness the unfrequency in our times 
of famines and their direful consequences ; the improve- 
ment, even in old and long cultivated countries, in the pro¬ 
ductiveness of those very soils which once yielded but a 
scanty pittance; the facilities of transportation, which 
enhance immeasurably the value of every production of art 
and labor, and the multitude of positive pleasures, before 
unknown to the human race, which are now added to the 
value of existence by the conquests of intellect over mate¬ 
rial things. Bring into the account, the intimate connexion 
between improvement in the useful arts, and every other 
kind of advancement in society, and add, if you please, the 
fact (of which I will not detain you with the proof,) that 


6 


MR JOHNSON’S LECTURE. 


the reign of the useful arts is the reign of common sense, 
and further, that the freedom and encouragement enjoyed 
by these arts, is, in every nation, the measure or exponent 
of that nation’s freedom in every other particular. It is 
not meant to assert that the most absolute and the most 
arbitrary despot may not occasionally offer what he may 
call encouragement to the useful arts. But then it is merely 
the deceitful lure of patronage, a thing which, when coming 
from such a quarter, is found to insult as often as it pro¬ 
tects the object of its care. This is not an occasion for 
tracing minutely the line of distinction between the ancient 
and the modern policy for encouraging the arts, or pro¬ 
moting inventive genius. Suffice it to say, that among the 
means of effecting these ends, due solely to modern times, 
is the plan of founding institutions expressly intended for 
instruction in practical science. You need not be informed 
that the institutions of learning existing previous to the 
time of establishing the modern schools of art, whether 
they professed to convey instruction to ihe young or to ex¬ 
ercise the talents of the mature in age, were far remote from 
that practical usefulness which the state of society de¬ 
manded. Not only had their pursuits no direct connexion 
with the useful arts, but those who were formed by their 
studies and discipline generally, regarded all contact with 
artizans and their vocations, as a species of contamination, 
most devoutly to be shunned. To be suspected of a 
design to turn one’s knowledge of abstract or of physical 
science to practical account, was deemed next to the sordid 
meanness of the felon or the traitor ; — and many a sense¬ 
less sneer has been uttered against those who by word or 
action manifested that they preferred a fund of useful 
knowledge to the vaunted discipline of scholastic logic and 
casuistical or metaphysical learning. This state of things 
could not, however, be perpetual ; the increasing lights 
which science, imperfectly applied, had shed upon the 
condition of social life, prepared the way for the more per¬ 
fect philosophical day. When the darkness and oppres¬ 
sion of the middle ages had past, and men had begun to 
return to sound reason, after the senseless and protracted 
wars of the crusades, they felt in all its atrocity the cruelty 
of that fanaticism which had sacrificed so many millions of 
human beings, and entailed misery on so many additional 


SCHOOLS OF THE ARTS. 


1 


millions, in a cause, in which the great mass of society 
had no actual or conceivable interest. 

Again, after that peculiar organization of society, which 
grew out of the crusades, — 1 mean the feudal system,— 
had for a few hundred years exercised its tyrannical influ¬ 
ence on the lives and fortunes of mankind, they began to 
perceive that human happiness was not the end and aim of 
their toils, their prowess, and their sufferings. They felt 
that pride of soul and arrogant pretension, were allowed to 
reap the fruit of honest industry ; while the true benefac¬ 
tors of society, were commonly ground to the dust, by all 
the devices which selfishness and despotism could invent. 
Since the eyes of civilized nations have thus, within the 
last half century, been opened to the true distinction of 
merit, there has been less apparent disposition to cultivate 
national antipathies and to promote wars of conquest. This 
age has been distinguished by a pacific spirit, and, of course, 
by the cultivation of those arts which render the state of 
peace glorious and happy. 

In like manner, when it became apparent, from the de- 
velopements of philosophy, that the beneficent provisions 
of nature for the comfort and well being of man, were but 
partially understood and appreciated, — when it was felt 
that they who toiled in the useful arts, were in no degree 
valued or compensated according to the intrinsic impor¬ 
tance of their services to mankind, — when men became 
alive to the fact, that the soldier of fortune, though perhaps 
a worthless man, was often extolled, caressed, and deified, 
while the most powerful intellect, the most pure morality, 
the most devoted patriotism, the most admirable skill and 
patient industry, were allowed to languish in obscurity,— 
thef naturally sought the means of correcting to some ex¬ 
tent this glaring injustice in the allotments of society. 
From this consideration and from a laudable zeal to build 
up the character of their age and nation on a more endur¬ 
ing basis, than had hitherto been laid, the friends of human 
happiness, devised the plan of diffusive instruction, and 
mutual co-operation in the enlargement of intellectual 
resources, among the industrious classes of society. 

To perceive the important bearing of a union of efforts 
thus directed, we may refer to the analogous but more ex¬ 
tensive operation of learned men to promote the cultivation 


8 


MR JOHNSON’S LECTURE. 


of science. The difference will be, that while schools of 
art are of limited extent, and are local in their nature, the 
scientific association is capable of embracing whole nations, 
or entire continents. 

The cultivators of science, seem to have arrived at the 
conclusion, that the ancient organization of societies, can 
no longer carry forward the glorious ensigns of their cause. 
Personal prejudices and predilections are not found to be fit 
counterpoises to talent and moral worth. Those who have 
no philosophical importance are not now believed to be the 
best judges of scientific merit; those who, in the character 
of parasites, clung closest to men, are not in these days 
deemed the most respectable orders of creation ; and the 
high grounds of science are not thought to be the most suita¬ 
ble arenas, into which pigmies should be brought to exhibit 
their puny dexterity. Men who value knowledge aright, 
cannot consent that her resources should be wasted, or her 
honors monopolized, by the weak who cannot, or by the 
indolent who will not, put forth an arm to sustain her char¬ 
acter. 

They are accordingly forming, or rather executing larger, 
more liberal, and, we may add, more republican plans of 
promoting the interests of truth. 

In Germany, Great Britain, and more recently, in 
France, voluntary associations have annually convened, 
bearing to science the same relation, which this Institute 
bears to education, to deliberate on the condition and pros¬ 
pects of philosophy, and to devise means for its more effec¬ 
tual and systematic cultivation. A natural result of these 
united labors, is a clearer comprehension of the whole 
ground of scientific inquiry, frequent luminous surveys of 
its distinct fields, a facility of collecting the valuable results 
of all current investigations, and the exposition of points 
towards which observation and experiment still require to 
be directed, or to which mathematical analysis may be 
profitably applied. An incidental result of such extended 
associations, is the division of labor which it introduces into 
the operations of the active experimenters, the working- 
men of science. The efforts of many a mind have been 
paralyzed by the fact that no kindred spirits were at hand 
to cheer it onward amid toilsome efforts in its peculiar 
province, to rejoice in its success, or sympathize in its dis- 


SCHOOLS OF THE ARTS. 


9 


appointments. The peculiar nature of its pursuits did not 
harmonize with the prevalent habits of those in its immedi¬ 
ate neighborhood, and it was compelled either to forego 
the advantage of a social feeling, or to (all into pursuits 
uncongenial to its nature. 

But since a general understanding among the cultivators 
of the same branch or subdivision of science has been es¬ 
tablished, the most remote and solitary toils of every votary 
will find their appropriate stimulus, in the consciousness 
that a point of union can soon be found, to which the ac¬ 
quisition made, may at once be carried, with the certainty 
of being greeted with honor and reward. And even if the 
narrow and grovelling spirit of envy should seek to excite 
local, personal jealousies against the man of true merit; if 
petty meanness strive to wrest from the deserving the credit 
of their ow n labors, or to throw doubt and distrust around 
the lights of truth and justice, still will the noble efforts of 
genius be unremitted ; still will the certainty of a tribunal 
superior to the influences of detraction, impel it to useful 
labor, and secure to mankind the results of its exertions. 
So, too, do schools and associations for promoting the arts, 
afford centres of action, towards which the ingenuity of the 
artizan may direct its energy and find a reciprocation of 
sentiments, or a communication of light for the guidance of 
its efforts. We may indeed regard these two contemporary 
forms of society, the one for advancing general science and 
the other for promoting the arts which depend upon its 
principles, to be most happily conjoined for mutual benefit. 

So intimate is the connexion between the improvement 
in arts and the cultivation of physical science, that we shall 
in many cases find it impossible to separate the considera¬ 
tion of an art from that of the science of which it may have 
been either the offspring or the parent. In admitting, 
however, that science has often ow'ed its very birth to the 
arts, we mean, of course, nothing more than that the latter 
have discovered by practice, particular truths, which the 
former has afterwards, by direct experiment, by analysis, 
and by general reasoning, converted into comprehensive 
laws to regulate future practice. The truth seems to be, 
that art has in such cases obeyed laws of nature, before sci¬ 
ence had discovered or announced their existence ; but, to 
convert this fact into an argument against the utility of study- 


10 


MR JOHNSON S LECTURE. 


ing the sciences, is, in reality, no less than to assert that it 
were better to owe all our principles of action to accidental 
discoveries, rather than to take them ready formed from 
the hands of philosophy. 

While the wants of society are few in number, and the 
habits of men fixed, the means of gratifying the former and 
of sustaining the latter, are alike simple. In this state of 
things, the provision of any peculiar instruction, adapted to 
qualify particular individuals or classes for the prosecution 
of refinements in art, would be doubtless looked upon as 
chimerical. The establishment of a school for shepherds, 
an academy for fishermen, or an institute for hunters, would 
be little less than ridiculous ; and were all society in this 
primitive state, or were there any, the remotest, probability 
that such would soon be its condition, we should think the 
time required to compose a discourse on such a theme, very 
unprofitably employed. Laying aside, however, every idea 
that the dreams of those social reformers, who found their 
expectations on a supposed retrograde movement in human 
affairs, we will assume the actual and probable condition of 
society, as the basis of our observations, and will endeavor 
to demonstrate the necessity for schools of the arts, —we 
will next ask your attention to the history of those estab¬ 
lishments which have been erected for this purpose, — and 
endeavor to delineate their character, objects and effects. 

That schools appropriated to the arts, (by which we in¬ 
tend at present to designate the useful arts,) those which 
depend on a knowledge and application of science, are 
necessary, will be abundantly evident when we consider 
how intimately the arts in question are interwoven with the 
great plans of social organization, and how closely the very 
well-being of society is allied to the successful prosecution 
of those arts to which science is peculiarly applicable. If, 
indeed, all the arts were simple handicrafts, we might send 
those who aspired to eminence in any one of them, to the 
workshop of the artizan, and bid them glean from the rou¬ 
tine of manual labor, all the skill which their sanguine 
wishes may have prompted them to expect. And, if in the 
course of events, the art which had been learned were never 
destined to undergo a change, the trade acquired would be 
a permanent acquisition, liable only to the vicissitudes 
which affect all the great interests of mankind. But is this 


SCHOOLS OF THE ARTS. 


II 


a true picture of the useful arts ? Is there any important 
department of them in which, to insure success, some de¬ 
gree of general science is not at this day demanded ? 

Is it true, that no progress is made, no new facilities 
acquired, which all, who would successfully prosecute their 
labors, must adopt, or else be content to see others out¬ 
stripping them in the extent and profits of their industry ? 
Is it true that the possession of principles of science has 
nothing to do with this self-adaptation to new and varying 
circumstances ? Or is it not, on the contrary, undeniably 
true, that he only can be pronounced certainly secure of 
his gains, who not only has skill in his hand , but the seeds 
of other forms of skill in his head! But personal thrift 
seldom needs more than its own stimulants, and this is 
the lowest motive which should impel us to encourage the 
dissemination of those sciences which belong to the useful 
arts. In the desire to establish the full dominion of man 
over the physical creation, to place the citizens of our 
country in possession of all the blessings which nature has 
scattered around them, to overcome the natural obstacles 
which impede the free intercourse of the different parts of 
our extended country, to make known the treasures of the 
forest, the field, the river and the ocean, — to bring from 
the deep caverns of the mine, the wealth of our exhaustless 
mineral stores, and the no less gratifying facts of geological 
science, — these, become in the mind of the patriot and 
the philanthropist, motives of higher and nobler energy. 
But laying even these inducements for a moment out of 
the question, let us contemplate the case as between our¬ 
selves and other nations, not in a commercial, but a domes¬ 
tic point of view. Our admirable constitution, in its liberal 
dispensation of the blessings of freedom, and of free gov¬ 
ernment, has allowed full liberty to foreigners of every 
name to prosecute among us their several plans of industry 
and of profit. The natural riches of our country are fully 
understood abroad ; and among the nations of Europe, 
schools of art have been so long and so effectually applied 
to the purposes of individual and national improvement, 
that the success of well instructed artizans and directors of 
works, emigrating to this country is no longer a matter of 
doubt. They will, therefore, prepare if we do not, to take 
advantage of the bounty of nature ; and when we find for- 

3 


12 


MR JOHNSON S LECTURE. 


eigners alone, with foreign capital, and foreign labor, in 
effect monopolizing the mines, the public improvements, 
nay, the very highways and water courses of our country, 
we may thank our own supineness for the deprivation 
which we shall suffer. To prove that this view of the case 
is not fanciful, let us cast a glance at the operations un¬ 
dertaken on our own soil. We shall find not a few of our 
gold, iron, and coal mines, and divers extensive manufac¬ 
turing establishments, directed and controlled, if not en¬ 
tirely owned by foreigners. This is said with no desire to 
create or awaken an undue jealousy towards those enter¬ 
prising individuals, who have sought our shores, with the 
purpose of reaping a share in that harvest of good which is 
spread out before the eye of intelligence and industry. 
We would use the fact as a motive for self-defence against 
the future degradation of native talent, and the entire ap¬ 
propriation by other than American citizens, of the richest 
fruits of enterprise. And how shall this self-defence be 
effected ? Certainly, by no other means than those of fair 
and honorable competition, by well instructed artizans and 
men of practical science. And who does not know that 
such men are to be formed only by a peculiar course of 
discipline and instruction, and only with certainty, in places 
of instruction adapted to such purposes. That other 
places of education do not, except incidentally, effect the 
object, is not at all surprising, when we consider that they 
were mainly intended for other purposes, — for purposes 
which they are generally believed to fulfil. It is no re¬ 
proach to a school of medicine, that it does not form law¬ 
yers, and perhaps none to a school of theology that it 
seldom or never sends forth good statesmen. Neither would 
we charge it as a dereliction of duty upon a “ school of the 
prophets,” whether legal, theological, medical, or political, 
that it only by a rare combination of accidents, becomes 
the foster parent of a thorough mechanist, a skilful engi¬ 
neer, a successful miner, a good manufacturing chemist, a 
discriminating assayer, an able architect, a profound metal¬ 
lurgist, or even a productive working-man in science. But 
with all these useful classes, the establishments of practical 
science in Europe, will supply our country if she do not 
supply herself. And the question is only in what manner, 
and by what means and appliances, shall the objects of a 
domestic supply be effected ? 


SCHOOLS OF THE ARTS. 


IS 


But we have other and urgent reasons, why institutions 
of the nature which we have indicated, ought to be estab¬ 
lished and fostered in our republic. And granting that 
even the guarantee of national independence, did not re¬ 
quire that the useful arts should be fostered and protected 
among us, (a point which we are not now going to discuss), 
is there nothing in our feelings, as men and citizens, which 
should impel us to wish for their continued success ? Is there 
nothing, for example, of mortified pride, in the fact, that on 
the very thoroughfares of our internal commerce, in their 
latest, most approved form, nearly the whole superior struc¬ 
ture, is the product of foreign art? Are we not chagrined 
at the fact, that having gone to foreign lands to borrow 
capital, we are compelled to send it back to foreign arti- 
zans to procure the very materials over which the merchan¬ 
dize is to be transported, that must repay the debts we have 
contracted ; and that these materials are for hundreds of 
miles in extent laid upon the surface over beds of the same 
ore of unsurpassed richness, accompanied by all the means 
required for their developement and preparation, and only 
lying unheeded through the want of skill and enterprise to 
bring them to a useful form ; and must we be compelled to 
witness the moving agents, too, wrought by the hands of 
strangers, and inferior to what might be produced among 
ourselves, vaporing away over our meek dependence, bear¬ 
ing along the gorgeous trains, and belching forth their 
scorn at our want of self-respect, and of patriotic pride ? 
Such things are in a thousand forms displaying them¬ 
selves before us, if we will but open our eyes to their exist¬ 
ence, and not wink in collusion at the national discredit 
which they imply. 

Our remarks thus far, have been confined to the effect of 
schools of art, upon the arts themselves. As to their effect 
upon the artizans in elevating their character, preparing 
them for the successful prosecution not only of their re¬ 
spective callings but also of all the duties of citizens, we 
cannot for a moment entertain a doubt. Awaken and em¬ 
ploy and strengthen one practical talent, and you have 
done more towards making a good citizen than if you had, 
without producing this result, stored his mind or his imag¬ 
ination with all the lore of a hundred ages. A school of 
arts, then, should seem to be no less important in a civil- 


14 


MR JOHNSON’S LECTURE. 

ized community than one for literature or abstract science. 
That this is not the opinion of one or of a few individuals 
the progress which they have already made will sufficiently 
testify. 

We have stated some of the general historical facts con¬ 
nected with the originating of schools and institutions for 
the purposes of which we have been speaking. If we 
would know to what period their foundation is to be re¬ 
ferred we need not perhaps go further back than the last 
quarter of the eighteenth century. Whatever institutions 
had before that period been devoted to the sciences, had 
generally copied with more or less precision the ancient char¬ 
acter, and had deviated but little from the usages of past 
centuries. 

From the moment when France, rising amidst a fearful 
convulsion from beneath that load of oppression under 
which she had so long groaned, began to cast about a 
scrutinizing glance at the causes which had paralyzed her 
industry and cramped her resources, she found that a want 
of general information in regard to the actual character of 
her mineral treasures, and to the processes, and methods to 
be adopted in mining operations had made her in a great 
measure dependent on Sweden, Russia and other nations 
for the supply of one of the most indispensable articles of 
general consumption ; and this too while iron ore abounded 
in her own soil, where wood, coal, and all the means for 
its reduction were in the utmost plenty. In short, she was 
then in almost precisely the same situation with regard to 
this product of industry, as that in which we stand at this 
day. It was from a view of this particular case, that intel¬ 
ligent men in France determined on the establishment of 
an institution expressly devoted to those practical sciences 
which concern the art of mining. Hence originated the 
celebrated school of mines which by means of its instruc¬ 
tions, its collections, the productions of its laboratories, and 
the extensive circulation of its journal, has done so much 
for improvement in that branch of art. The establishment 
was made a national concern, for the obvious reasons that 
the interest it sought to promote was national interest. 

The impulse for establishing schools of art thus given, 
was extended to various other subjects, and resulted in the 
formation of the Polytechnic school, so much cherished by 


# 


SCHOOLS OF THE ARTS. 


15 


Napoleon, and which has given to Fiance so many able 
men distinguished alike in war and in peace, in art and in 
science. Into Great Britain the spirit of practical scien¬ 
tific instruction, was introduced in 1796, by Dr Anderson, 
in the foundation of a class for practical men and in the 
provision of means for supporting a distinct institution 
devoted to the interests of mechanics. From this model 
have been formed innumerable societies and institutions for 
subserving the general purpose of the arts. Instead how¬ 
ever of receiving any very efficient support from the con¬ 
stituted authorities, they were in general left to the voluntary 
exertions of those who chose to enrol themselves as mem¬ 
bers, and sustain their share in the burthen of their main¬ 
tenance. This has subjected them to some serious in¬ 
conveniences. Though enjoying the vigor of popular 
institutions they have also occasionally felt the uncertainty 
of a reliance on a mere subscription list, for carrying into 
effect the useful plans which they had contemplated. They 
have also been subject to the pernicious influence of a dis¬ 
position to narrow the limits of their usefulness by persons 
who having no regard for the real interests of the artizan, 
have apparently sought to mix in their affairs only to re¬ 
strain their efforts, limit their instructions to a few paltry 
objects, or to derive from them some support to other 
institutions, which wanting a popular character, wanted 
also the favor of the public. 

The rapid multiplication of societies for the purposes of 
popular instruction, in England, France, Belgium, and the 
United States furnishes the most conclusive evidence of the 
high degree of approbation with which the laboring classes 
have hailed this new accession to their sources of pleasure 
and of usefulness. They have also met a favorable recep¬ 
tion in various parts of Germany and besides the “ Gew- 
erbverein ” or Association for encouraging industry at 
Berlin, we find similar institutions at Achen, Enfurt, 
Goerlitz, Muhlhause, Suhl, Breslaw, Sagon, Greifswalde 
and Dantzic. 

It has been the fortune of these establishments to en¬ 
counter some indirect opposition, but really to suffer from 
it no material injury. Their fate has been almost the 
reverse of that which has often awaited the plan of univer¬ 
sal education by common schools ; — for while, of the latter, 



16 


MR JOHNSON’S LECTURE. 


many have spoken as if they believed the great truth that 
our peace, honor, happiness, and national existence, de¬ 
pended on the universal prevalence of intelligence and 
good morals, they have acted as if they supposed such a 
notion to be utterly false ; — whereas, in regard to the 
practical sciences and the useful arts, though persons some¬ 
times indulge a peccant humor, and make up a pretty de¬ 
clamation against what they call studying facts , pursuing 
utility , ‘ the rage for improvement , and the like edifying 
topics of reproach, yet they have in general the good sense 
not to adopt in practice the spirit of their own harangues. 
Oh no, — they prefer comfort to discomfort. 

I have referred to the fact, that by far the greater num¬ 
ber of schools of art have been mere voluntary associations, 
deriving no aid even in their establishment, from the public 
resources, to which notwithstanding they so largely contri¬ 
bute. It seems probable that a more efficient and decided 
tone will hereafter be given to their movements, and that 
some plan of public endowment and support, similar to 
that which was so ably sketched a few years since by a 
committee of the legislature of Massachusetts, will ere 
long be demanded by the public voice. A central school 
for each state, would thus become a point of united interest 
for the public at large, and for the intelligent artizan of 
every name. It is inconceivable that any doubt should 
have been entertained as to the salutary effect of such an 
institution, on the character and operations of other sem¬ 
inaries of learning. In an establishment of this nature, 
with which it has been my fortune to be for some years 
connected, no class of the members are more constant in 
their attendance or more efficient in their services, than 
teachers and professors of every rank. Uniting frequently 
with great numbers of practical men in the pursuit of a 
common object, they derive from the intercourse, light and 
information which neither books, nor solitary study nor 
even the refinements of a more exclusive society would 
afford. 

The several objects of well-constituted schools of art are, 
instruction by lectures or in such other modes as the 
nature of the case demands, encouragement to artizans by 
rewards adjudged to meritorious productions or inventions, 
diffusion of information by means of the press, and finally, 


SCHOOLS OF THE ARTS. 


17 


the prosecution of researches in natural history and of ex¬ 
perimental inquiries in chemistry, philosophy "and kindred 
subjects. On the first and the last of these a few remarks 
may not be improper. 

The purpose of the instruction in a practical school, it 
should be remembered, is not to teach trades, but only the 
principles applicable to them. It should enlarge the sphere 
of the student’s observation, by placing around him, in well 
stored collections, cabinets and workshops, the objects with 
which he ought to become familiar, and with these he 
should acquire by study and manipulation, a perfect ac¬ 
quaintance. The manual labor performed might all have 
a reference to the wants of the school, hence a partial ac¬ 
quaintance at least with the trade of the joiner, the turner, 
the founder and the mechanist, would of course be acquired, 
and these in addition to the use of the blow-pipe, the en- 
ameller’s lamp and similar implements, would soon render 
an institution independent to a great degree on external aid 
for the supply of models for illustration, and of instruments 
for research. If placed in a situation where the arts of 
gardening and of agriculture can be introduced, the pursuit 
of these objects for both instruction and profit would nat¬ 
urally constitute a part of the plan. But what appears to 
merit more attention than has hitherto been given to it, in 
the institutions of our country, is the pursuit of experi¬ 
mental inquiries, respecting those scientific subjects with 
which the useful arts are mostly conversant. 

Among the physical sciences, some are now so far 
reduced to mathematical laws as to constitute almost per¬ 
fect departments of positive philosophy. But, in order to 
become practically useful, the mathematical principles 
which they embrace, must be taken with certain modifica¬ 
tions, with which, from the nature of things, they are in 
practice always combined. These modifying causes are the 
objects of separate and independent inquiry, and constitute 
departments of special science, peculiarly interesting in 
practice, and only to be accurately ascertained by experi¬ 
mental researches. Abstract science then lends her aid to 
combine the results, with her general deductions, and to 
reduce the whole to a form in which they may be used by 
practical men. 

Some few of these once void spaces in practical know- 


18 


MR JOHNSON’S LECTURE, 


ledge have already been filled up ; as examples of which 
we might refer to the researches in regard to elastic vapors, 
— to the resistance of friction, — to the rate of cooling and 
other phenomena of heat, — to the best forms of bodies, 
designed to move through liquids, — to the strength of 
solid and of fibrous materials respectively, and the extent 
to which strains and pressures may be carried without pro¬ 
ducing permanent changes of form. These are a very few 
of the cases in which it has been attempted to determine 
by laborious experiment, the special laws of practical science. 

But the points of absolute certainty, hitherto obtained, 
are, it must be confessed, few and far between. There is a 
harvest, for untold generations of inquirers yet to reap. 
They have no need to wander abroad into the thorny paths 
of doubtful disputation. Let them bring sincere and un¬ 
biassed minds, to the shrine of that truth which has been 
written by the hand of Omnipotence, on every page of the 
vast volume of nature, and they cannot fail to understand 
her language, — a language which though to the incurious 
it may seem an insignificant hieroglyphic, will one day 
stand revealed to some future interpreter, who entering 
Champollion-like into the great temple, shall bid defiance to 
obscurity,—lift the veil of time, and read into intelligible 
“ phonetus ” these mysterious symbols. 

The vigorous prosecution of experimental science can¬ 
not with justice be referred to a period more remote than the 
age of Torricelli and Pascal, about two centuries ago. In¬ 
deed it has been asserted that the crucial experiment of the 
latter, by which he tested, beyond all controversy the truth 
of Torricelli’s theory of the barometer — gave the first 
great impulse to the experimental method of inquiry, since 
which time the confidence of mankind in this method has 
been constantly growing stronger and stronger by every 
fresh evidence of its importance. To be impressed with 
the magnitude of its power we need but to mention a few 
facts. It had been observed at a very remote period that 
amber when rubbed was capable of attracting light sub¬ 
stances, — but no developement was given because none 
could be given, to this most interesting observation, until 
the experimental method of inquiry pointed the way to 
those brilliant discoveries and useful applications which 
have been constantly increasing in number and importance 


SCHOOLS OF THE ARTS. 


19 


within the last seventyfive years. Again, it was observed 
before the days of Aristotle, that a certain ferruginous, 
mineral, then called magnus was capable of attaching to 
itself, as by some invisible power, small pieces of iron or 
steel. The philosophical toy of that day, has become, 
through the aid of experimental science, the guide and 
safeguard of the commercial enterprise and the naval power 
of every nation on the globe. 

And again, while the principle of magnetism was thus, 
for a long period, made subservient to the interests of man, 
its nature and its relations to the other subtle agents of the 
universe have remained almost unknown until the same 
method of pursuing philosophy, taking a useful hint from 
significant indications, presented by electricity when acting 
on the compass needle, has since 1820, opened one of the 
most enchanting fields of both abstract and experimental 
research. So that instead of regarding the globe which 
we inhabit as one gigantic loadstone, it is beginning to be 
doubted whether its ferruginous ingredients, have really 
anything of importance to do with its directive power, 
except it be to disturb occasionally the general action of 
that force. This exemplifies the value of the same method 
in the formation or the correction of theoretical views. 
But what qualifications ought they to possess who are, by 
this method to advance the limits of science ? 

The prosecution of experiments with a view to practical 
and useful results, requires a combination of talents and ac¬ 
quisitions not frequently united in the same individual. 
The possession of a mind disciplined and accustomed to 
dwell intently on the object of its search; a habit of ob¬ 
serving with minuteness the incidental, no less than the 
general phenomena of things ; a patience and calmness in 
watching the progress of one’s own labors ; a familiarity 
with the mathematical and other scientific methods of ap¬ 
plying the results of experiment, which may lead to the 
formation of general laws ; — all these are indispensable in 
one who would extend the boundaries of science. Add to 
this, a mind fair and free from the trammels of hypothetical 
despotism, — ready to follow truth wherever she may lead, 
and willing to be instructed by facts , however contrary to 
the dogmas and theories of closet philosophy. Nor are the 
qualifications of mind alone to be studied in the formation 

4 


20 


MR JOHNSON’S LECTURE. 


of a good experimenter. There must be some readiness in 
devising, combining, and adjusting apparatus; some inge¬ 
nuity in constructing, at least in model, the implements of 
research which he would employ. There must be a famil¬ 
iarity with principles that shall enable the inquirer to judge 
of the proper adaptation of means to ends, so as to avoid 
the mortification of failures and the loss of time and re¬ 
sources. 

In every department of philosophical investigation, the 
characteristics just enumerated are indispensable, but they 
become doubly important, when the purpose of the inquiry 
is not so much to trace out new paths of philosophy, as to 
ascertain the exact measure and bearing of those which 
have already been roughly surveyed. Just in proportion as 
Science becomes exact and practical , does the demand for 
exact and practical talents in its investigations become the 
more urgent. How absurd then, is it, to imagine that a 
corps of experimenters to prosecute difficult, and delicate 
inquiries, can be called forth from the promiscuous ranks of 
mankind ! and how evident is the conclusion, that those 
who would make human knowledge either more profound 
or more exact, must be trained by study and practice to the 
duties which they would undertake. The necessity for 
schools of experimental philosophy, where such practice 
may be attained, is evident upon a moment’s consideration. 

Now it is exactly this power of co-ordinating knowledge, 
of showing within what limits practice may safely rely on 
the deductions of theory, to what extent modifying causes 
must be taken into the account, and how far the imple¬ 
ments and materials which man can command, are adequate 
to carry out and realize the results of his speculative inves¬ 
tigations. It is this power which alone is capable of making 
available the truths of theoretical science, and this is the 
kind of power which a school of arts is fitted to develope. 
It is in institutions of this nature, that have been formed 
the most distinguished experimenters of Europe ; and in 
such establishments as the Polytechnic school, and the 
School of Mines at Paris, the Royal Institution in Lon¬ 
don, and the Andersonian at Glasgow, the prosecution of 
these inquiries has conferred not less honor on theoretical 
science, than benefit on the useful arts. 

The purpose of schools of the arts is not, however, merely 


SCHOOLS OF THE ARTS. 


21 


to give so much mechanical information as will qualify 
men for manual toil. They have the farther and more im¬ 
portant object of enlarging the sphere of observation and 
reflection, of adorning and dignifying the character of the 
artizan. By learning to bring the principles of nature and 
of art to the test of experiment, the diligent cultivator of 
practical science becomes habituated to regard with most 
favor those precepts of moral conduct which will best bear 
the same test; and to look with distrust on those which 
shrink from such a trial. If he have diligently sought truth 
at original sources, at the very fountain-head, among the 
works of the Creator, his mind is in no fit condition to relish 
the mazy and misty wanderings of doubtful speculation. 

Another point of view in which we may contemplate 
schools of art, regards them as conducive to the well-being 
of society, by stimulating the mind to the pursuit of know r - 
ledge for recreation as well as for interest , and thus taking 
the place of other resorts and other stimulants, which, un¬ 
fortunately, too often usurp possession of the bodies and 
souls of our fellow men. Besides furnishing the commu¬ 
nity with the best artizans in every department, and good 
citizens fitted to serve their country in the most acceptable 
manner, besides making men practical in their habits, ra¬ 
tional in their tastes, less prone than formerly to crowd 
certain professions where success is at best doubtful, and 
more inclined to seek the substantial, than the fanciful dis¬ 
tinctions and rewards of merit, they tend to the develope- 
ment of the national resources, and to the cultivation of a 
national self-respect. Besides proving the nurseries of 
powerful intellect, and aiding in the co-ordination of ob¬ 
served facts, they become the posts where instruction 
may recruit her ranks, and where the independence of a 
nation may find its ablest and most effective supporters. 











\ 




































































































































































REPORT 


OF THE 

COMMITTEE OF THE FRANKLIN INSTITUTE 

OF THE 

STATE OF PENNSYLVANIA, FOR THE PROMOTION OF THE MECHANIC ARTS, 

ON THE 

EXPLOSIONS OF STEAM BOILERS, 

OF 

EXPERIMENTS 

MADE AT THE REQUEST OF THE TREASURY DEPARTMENT OF 

THE UNITED STATES. 

PART II. 


CONTAINING 

THE REPORT 

OF THE 

SUB-COMMITTEE, 

TO WHOM 

WAS REFERRED THE EXAMINATION 
OF THE 

STRENGTH OF MATERIALS 

EMPLOYED 

IN THE CONSTRUCTION OF STEAM BOILERS. 


- 0 -- 0 — 


PHILADELPHIA: 
PRINTED BY MEltRIHEW fc GUNN, 

No. 7 , CARTER’S ALLEY. 


1837. 





Philadelphia, December 30 th, 1836. 

At a meeting of the committee of the Franklin Institute, of the State of Pennsyl¬ 
vania, for the promotion of the Mechanic Arts, on the Explosions of Steam-boilers, 
held this day at the Hall of the Institute, Prof. Walter R. Johnson, chairman of the 
sub-committee on the Strength of Materials, presented a report of the Experiments 
on the subjects assigned to that'sub-committee, which was on motion read, accepted, 
and ordered to be printed. 

S. V. MERRICK, Chairman. 


Philadelphia , July , 1837. 

Presented to the Board of Managers of the Franklin Institute of the State of 
Pennsylvania, for the promotion of the Mechanic Arts, and approved. 

JOHN STRUTHERS, Chairman . 


Attest, William Hamilton, Actuary, 


CONTENTS. 


Preliminary remarks—subjects of investigation, 

Machine for proving the strength of materials, . 

Friction of the machine, ..... 
Elasticity of the machine, .... 

Sources from which the materials were obtained, 

Preparation and gauging of the specimens, 

Apparatus for high temperatures, . . . 

Standard for high temperatures,—steam pyrometer, 

Mode of ascertaining the weight of vapour expended, 

The revolving counterpoise, .... 

Condenser of the steam pyrometer, .... 
Specific heat of iron, ..... 

Bath for heating the standard piece, .... 

The cooling apparatus for specific heat. 

Thermometer in the water vessel, .... 

Tables of specific heat, ..... 

Results of experiments on specific heat, 

Apparatus for the latent heat of vapour, 

Results of experiments on latent heat, 

Table of latent heat, ..... 

Specific heat of iron as determined by vaporization, 

Table of specific heat by vaporization, 

Heating and cooling of liquids, .... 
Synopsis of experiments on heating of liquids by immersing 
body, ..... 

Heating by contact of air, ..... 

Table of do. . . 

Strength of rolled copper, ..... 
Tables of experiments on strength of copper, 

Effect of increased temperature on copper, . 

Table of experiments to obtain the law of tenacity in copper 
pendent on temperature, .... 

Extensibility of copper, .... 

Strength of boiler-iron at ordinary temperatures, 

Tables of experiments on boiler-iron, 

Methods of manufacturing boiler-iron, 

Table of the relative advantages of different modes of making boile 
iron, . ..... 

Strength of boiler-iron manufactured by different processes, . 
Strength of iron made by other processes than rolling into boile 
plate, • ...... 


Page 3 
5 
8 
10 
12 
13 

15 

16 

17 

18 

19 

20 
20 
21 
22 
24 
37 
41 
43 

44-5 

46 

47 

48 


ho 


as de 


8 - 


49 

54 

56 

57 
-73 
74 


76 
Page 78 

79 

80 
110 


146 

147 


147 





CONTENTS. 


Tables of experiments on bar iron, .... 

Results of experiments on wrought iron not rolled into plates, 
Strength of iron made from different sorts of pig metal, 

Tables of experiments on iron from different sorts of pig metal, 
Table of the influence of high temperatures on the tenacity of wrought 
iron, ....... 

Effect of high temperature on iron, ..... 

Elasticity of iron, ...... 

Second method of observing elasticities, .... 

Synoptical table of the elasticity of different bars of iron, 

'fable of areas of section after fracture, .... 

Diminution of area at the moment of fracture, 

Forces producing permanent elongations of iron, 

Strength of iron in different directions of the rolled sheet, 

Table of results of comparisons between bars cut in different directions, 
Specific gravity of boiler-iron, ..... 

Effect of repeated piling on the tenacity of plate iron, 

Effect of piling into the same plate, iron of different degrees of fineness, 
Effects of the rivets on the total strength of boilers, 

Table of the effects of unequal strains on rivet-holes, 

Construction of cylindrical boilers and flues, 

Effects of use and long exposure on the strength of boiler iron, 

Effect of annealing on the tenacity of iron, 

Concluding observation, .*.... 
Note, on the labours of some former experimenters, 

Index, ........ 


148 

188 

189 

192 

210 

212 

218 

219 

220 
222 
224 
226 
228 
232 
ibid 
ibid 
234 
ibid 

236 

237 
ibid 
242 

246 

247 

248 


ERRATA. 


Page 16, line 4 from the top, for “ w,w\" read W,W'. 

- 37, last line, for “ containgf read containing. 

- 62, column 6 of the table, transpose the Nos. 11 and 12. 

- 86, 4th column, opposite to the 14th mark , for. 155700, read .154700. 

- 140, last line, for .097542, read .007542. 

- 150, in account of bar 217, insert running out , before the word puddling. 

- 206, line first, for «r, read bar. 

- 211, in the upper line, second column in the table, for °577, read 577°. 

- 214, line 33 from the bottom, for 27604, read 27605. 

- 218, line 3d from the bottom, for 6, read 0. 

- 238, on the figure at the bottom, belonging to the note at the right hand, 

upper corner of the parallelogram, insert y» 

- 239, 2d line from the top, for “commence Fig. l.from ” read commence (Fig. 

1.) from. 

- 242, 2d line from the bottom, for “254 D,” read 224 D. 

On plate 2d for Table LXXIII. read Table LXXII., and on figure n f of the same 
plate, for 62295, read 62472. 

On plate 4, for near the right and left sides of the figure respectively, 

read W and W'. 













Flat, L 



iiiiiiiiiiiiiiiiiiDinufiiiniimiiiii 



C 


Drawn by IV.Masan 


MACMWffi V ©M PlOTIff© TEWACITT, 

























































































Flat* 1. 







































REPORT 


Of the Committee of the Franklin Institute of the State of Pennsylvania 
on the Explosions of Steam Boilers , of Experiments made at the re¬ 
quest of the Treasury Department of the United States. 

PART II. 

Containing the report of the sub-committee to whom was referred the ex¬ 
amination of the strength of the materials employed in the constniction 
of Steam Boilers. 


To the Committee of the Franklin Institute of the State of Pennsylvania, 

on the Explosions of Steam Boilers : 

Gentlemen —The sub-committee, to whom was referred the examina¬ 
tion of the strength of materials employed in the construction of Steam 
Boilers, beg leave to submit the following Report : 

While it is important to know the causes which may produce a dan¬ 
gerous developement of elastic forces in the interior of steam boilers, it is 
obviously not less so, to understand aright the efficacy of those means on 
which we rely for confining or controlling their energies. Hence, in inves¬ 
tigating the causes of explosions, it is both natural and expedient, to exa¬ 
mine separately those facts and principles which concern the divellent and 
the quiescent forces respectively. The number and variety of circum¬ 
stances, which affect the character and durability of materials of which 
steam boilers are formed, are probably not less than of those which tend to 
modify the action of the fluids which they contain. In this view of the 
importance to be attached to the subject of the strength of materials, it may 
be considered remarkable, that while numerous investigations have been 
made as to the causes of danger, so little should have been attempted in 
regard to the most direct and obvious means of security. Before the series 
of experiments here detailed had been commenced, the necessity for such 
an investigation had been repeatedly pointed out, in public and private 
lectures, on the steam engine; the reasons assigned for instituting the 
inquiry, being the very general and unsatisfactory nature of those results, 
which are given in practical treatises, respecting the strength of metals, as 
dependant on the mode of manufacture, and on the different temperatures 
and other circumstances to which they are exposed. We had, it is true, 

1 



4 


a considerable number of results, obtained at different periods, by experi¬ 
ments on the direct cohesion of wrought iron.* 

They were, however, in general, undertaken for purposes very different 
from those which prompted the present investigation. 

Few of the experimenters had in view the influence of temperatures on 
tenacity ; and even those data which they furnish for calculating the proper 
thickness of metal to be employed at ordinary temperatures, in constructing 
steam boilers are liable to much uncertainty, owing to the diversity in the 
results themselves. Laborious and protracted as has been this investigation, 
still the practical importance of the subject has appeared to warrant a care¬ 
ful survey, and a diligent comparison of the various facts which might in¬ 
fluence the practice of those who desire to attain a secure action in the 
steam boiler. 

Without entering therefore into all the delicate questions, which, had a 
mere scientific view been indulged, we might have been prompted to examine, 
it has been the aim of the committee to obtain and present such classes of 
facts as both scientific and practical men may make subservient to their 
respective purposes. 

The questions, which in the course of this inquiry, it has been found 
necessary to investigate, may be classed under three general divisions. 

1. Principal, 

2. Incidental, 

3. Subsidiary. 

1. Principal. 1. What is the absolute tenacity per square-inch bar of 
rolled boiler iron, at ordinary temperatures, and to what irregularities is it 
liable? 

2. The same for rolled copper ? 

3. What is the effect of increased temperature on the tenacity of iron and 
copper ? 

4. What is the tenacity of wrought iron, manufactured by other means 
than rolling into plates ;—as by rolling it into bars or rods, by hammering 
and wire-drawing ? 

5. What are the relative advantages of iron made by refining from dif¬ 
ferent sorts of pig metal and their mixtures ? 

6. What is the comparative value of sheet iron manufactured by the pro¬ 
cesses of puddling, blooming and piling respectively, and in the last case, 
what influence have repetitions of the process ? 


* The following brief table contains some of the general results, obtained by 
different authors, as the strength of wrought iron. 


Name of the Experimenter. 

Strength 

in lbs. 
per sq. 
inch. 

Name of the Experimenter. 

Strength 
in lbs. 
per sq. 
inch. 

Muschenbroek, .... 


73.100 

Telford—Swedish iron, . 


64.960 

Perronet—on square bars, 


61.C83 

Brown—Welsh iron, 


57.075 

Perronet—on round bars, 


60.086 

Brown—Swedish, 


49.796 

BufFon,. 


84.730 

P.rown—Russian iron, 


59.472 

Poleni,. 


63.390 

Martin— (Fr.) St. Chambaud iron, 


49.000 

Rennie—on il English iron,” . . 


55.843 

Martin—Fourchambauldt iron, * . 


47.964 

Brunei—‘‘Best English,” . . 


68.544 

Martin—Superior English, . 


52.823 

Brunei—“ Best-best English,” . 


72.352 

Martin—English best cable, . 


49.251 

Telford—Welsh iron, 


65.520 




Telford—Staffordshire iron, . 


60.928 

Rennie—Copper, .... 

• 

33.79* 
















5 


7. What is the effect of piling into the same slab, iron of different degrees 
of fineness ? 

8. What is the comparative tenacity of rolled iron, in the longitudinal, 
diagonal and transverse directions of the rolling respectively? 

9. What influence may be produced, by long and repeated use, towards 
modifying the character of boiler iron ? 

II. Incidental. 1 . What is the specific gravity of the specimens sub¬ 
mitted to examination ? 

2. What elasticity is found in the metals under different circumstances 
of the trial ? 

3. What relation exists between the force which will produce a perma¬ 
nent elongation in a bar, and that which will entirely overcome its tenacity ? 

4. What amount of elongation may the several kinds of metal undergo 
before fracture ? 

5. Does the amount of constriction or diminution of area, at the section 
of fracture, bear any relation to the absolute strength of the metals, to the 
direction in which the strips are cut from the plate, to the breadth and thick¬ 
ness of the strips themselves, or to the temperature under which the trial 
is made ? 

6. What is the effect of the rivets on the total strength of a boiler ? 

III. Subsidiary. 1. What is the friction of the apparatus employed to 
determine tenacities ? 

2. What is the amount of its elasticity ? 

3. What is the latent heat of the vapour of water ? 

4. What is the specific heat of iron, copper and glass, respectively ? 

5. What is the rate of heating of a given mass of liquid, when subjected 
to the direct action of a solid of higher temperature ? 

6. At what rate will the same mass of liquid change its temperature by 
the action of air alone ? 

From the foregoing statement, it will be seen that more than twenty dis¬ 
tinct topics have demanded the attention of the committee. They have 
felt strongly inclined to embrace some other points of great practical and 
scientific importance, but the time already unavoidably consumed, and the 
very limited means which the other branches of inquiry and experiment 
on explosion left to be appropriated to the purposes of this sub-committee, 
compelled the relinquishment, for the present, of those objects which do 
not immediately concern the construction and use of steam boilers. 

The discussion of the questions above enumerated, will necessarily follow 
an order somewhat different from that in which they are here stated. A 
view of the apparatus, employed by the committee, claims the first notice. 
The origin and preparation of the materials to be tested, will also precede 
the detail of experiments. 

Machine for proving the strength of materials. 

The apparatus used, by the committee, for the direct determination of 
the principal questions regarding the strength of the specimens submitted 
to examination, is represented in plate I. M is a strong frame of oak timber, 
the two longer sides five feet in length, fourteen inches deep, and six inches 
thick. 

The two shorter, or end pieces, which project beyond the sides to the 
distance of three inches, are each two feet eight inches long, seven and a 
half inches thick, and fourteen inches deep. 

Between the two side pieces, (one of which is in the figure removed, to 
exhibit the interior or working parts,) is a space fourteen and a half inches 


6 


wide, affording room for a screw, cross-head, guide-rods, connecting 
blocks and wedges, to hold the specimens under trial; and also for the 
heating apparatus in experiments at high temperatures. 

These four massive blocks or beams of timber, are held together by 
strong screw bolts, passing through mortises in the end pieces, along tenons 
into screw nuts imbedded in the timber of the longitudinal beams. 

The frame is supported, as represented in the figure, by four firm trussel 
legs, six inches square, tied together near the bottom, and fastened as well 
to the ties as to the frame above, by mortising and bolting. The top of the 
frame is three feet eight inches above the floor on which the machine rests. 

Through one end A, of the frame M, about six inches below the top, and 
centrally between the two side beams of the frame, passes the screw S, 2f 
inches in diameter, and three feet long, cut into threads of an inch apart. 
Near the head of the screw, is a neck turned rather deeper than the threads, 
to allow a clamp collar to embrace it; which, together with a strong cast 
iron plate, against which the head of the screw works, prevents any longi¬ 
tudinal motion of the screw itself. 

N is the box or nut of this screw which by the revolution of S, either 
approaches to or recedes from the end A of the frame; s, s, are two guide- 
rods, one on each side of the screw, level with its axis and near the inner 
faces of the longitudinal beams of the frame, serving to support a cross 
head that contains in its central ring the nut N, and embraces by loops at 
its extremities the two guide-rods. The purpose of these loops is to pre¬ 
vent the nut from turning by the revolution of the screw. 

The cross head thus secured is united by two strong straps or bars of 
iron i , i, 2 inches wide by half an inch thick, to a block of iron b, which is 
also furnished with two projecting arms that rest on the guide-rods already 
described. This block as well as the two others b' and b" is 4 inches long, 
4 inches deep, and If inches thick, being perforated centrally in the direc¬ 
tion of its thickness with a hole in the form of the frustum of a square pyra¬ 
mid, the purpose of which is to admit of wedges placed within them to hold 
the bars of metal under trial. A more detailed description of these will be 
given hereafter. 

The block b' is connected to b by a separate pair of straps i\ i\ and has 
arms reposing on the guide-rods, or when necessary, admitting a vertical 
semi-revolution, so as to be laid over backward between the straps i , i. 
This latter disposition of the block b' was made whenever specimens of 20 
or 30 inches in length were to be tried ; but when those of only a few inches 
in length were under trial, b' was used in the position represented in the 
figure. 

The block b" is connected by the strong iron straps i", i", which pass freely 
through a suitable opening in the head B of the frame, to the lever L. One 
of these straps is seen at e, the other being on the posterior side of the 
lever, with which they are united by means of a steel bolt turned with care 
and well polished. The straps are kept in place by a head, screw nut and 
washers, on the bolt. This lever is of the rectangular kind, the longer arm 
being horizontal, the shorter vertical, and the angular point being in the 
axis of a second or lower bolt which serves as a fulcrum. 

At the end next the frame, the lever has a breadth or depth of seven 
inches and a thickness of one inch. Towards the opposite extremity or 
that on which the weights are placed, it diminishes to a breadth of four 
inches, and a thickness of | of an inch. The upper edge of the beam is 
straight to within 24 inches of the broader end, where it curves upwards, 
affording a massive support for the upper bolt already described. In a ver- 


7 


tical direction beneath that bolt, and in the prolongation of the upper straight 
edge of the lever, is the position, as already indicated, of the second steel 
bolt, serving for a gudgeon, on which the lever turns. The distance between 
the axes of the two bolts is 2.914 inches, which is therefore the length of 
the shorter arm of the lever. The bolts are very nearly of the same diameter, 
being each about 1.086 inches. The lower bolt rests against a plate of 
cast iron, having suitable projecting cheeks, with bearings adapted for its 
reception. 

A strap from the top of each cheek comes down over the bolt, and is 
fastened with a thumb screw, to prevent the lever being thrown out of place 
by the recoil of the machine. The two guide-rods s, s, pass through this 
cast iron plate, as well as through that which serves as a collar to the screw 
head, S, on the opposite end of the frame. The lever is formed of the best 
wrought iron, and weighs 164 T 3 T pounds, the matter being so distributed 
that if not neutralized by counter weights, its effect in straining any bar at¬ 
tached horizontally to the upper bolt would have been equal to 2495| lbs. 
To obviate this, and to prevent the weight of the lever from adding any¬ 
thing to the friction, it is accurately counterpoised by means of weights C 
and C,' corresponding to the parts of its mass which they are respectively 
required to sustain. Thus the weight of C, the larger counterpoise, is 103 
pounds 12 ounces, that of C' 60 pounds 7 ounces. The former is, however, 
increased to counterpoise likewise, one-half the weight of the two straps 
i", i'\ the other half resting, as will be seen, on the horizontal guide-rods 
s, 's. 

The axes of the pullies p , p', over which the cords r, r' pass, are 
furnished with cavities to receive steel pivot-points, in order to reduce, as 
far as practicable, the friction of these parts. The diameter of these pullies 
is 12 inches. 

The iron stirrup, to which the cord r is attached, is applied to the lower 
bolt or fulcrum of the lever, the projecting ends of which roll on straight, 
horizontal edges, forming the bottom of two loops with which the stirrup is 
furnished. 

By means of the suspending apparatus above described, the lever is 
enabled to obey any force acting vertically on its longer arm, with the 
advantage of ample strength and stiffness, combined with the condition of a 
theoretical lever, in respect to the gravity of parts. 

There are two modes of operating by which a bar of metal, placed in 
the machine between b’ and b" might be broken, so as to ascertain the te¬ 
nacity. 

The first is to apply the force of the screw S to strain the bar in raising 
a weight W suspended at any convenient point on the arm h of the lever; 
the second is to employ the screw only to regulate the height of that arm, 
and to restore it when relieved of the weights, to the horizontal position, 
whenever the extension of the bar had allowed it to fall below that posi¬ 
tion. 

The latter method was with very few exceptions, adopted by the commit¬ 
tee,—both because it allowed of a more exact determination of the breaking 
weights, by a small addition at a time, and because it rendered the effect of 
the friction constant in its kind, being always in opposition to the gravitating 
force of the weight W, and subtractive , in the calculation.—In order to ap¬ 
ply this mode of action without requiring correction for the stiffness of the 
cord r' and the friction of the pulley p\ it was only necessary after adjusting 
the weight C', to remove so much as would allow the arm h of the lever to 
descend upon the slightest jarring of the machine. The tenacity of the bar 

1 * 


s 


and the friction at the fulcrum, were then the only resistances to the motion 
of the weight W. 

The purpose of the tackle of pullies P, is to elevate the scale pan and 
weight after they have descended to the floor, in order, by turning the 
screw S, to counteract the elongation of the bar under trial, and again to 
commence operations with the descending motion of the arm h. The 
power of the operator is applied to the tackle by means of the windlass w, 
furnished with its crank, ratchet wheel and click. The upper edge of the 
lever was graduated into parts distant from each other just ten times the 
length of the shorter arm. 

By the aid of these several appendages, the machine allows the most 
gradual additions to be made to the divellent force applied to the specimens, 
breaking each with a descending movement, and consequently, rendering 
the friction definite in the direction of its influence, being, as before stated, 
always subtractive. 

The very few cases in which the mode of operation rendered it additive, 
are particularly mentioned in the tables. 

At the outer extremity of the lever, and in the prolongation of its upper 
edge, is placed a style z , serving as an index to the graduated arc a, which 
is divided into minutes of a degree. The point of the style is 10 feet 3 inches 
from the axis of motion in the lever, and the length of the entire circum¬ 
ference which it would describe 772.8276 inches. Hence each degree 
is 2.14674 inches, and each minute, as measured on the arc, is .035779 of 
an inch. The whole extent of the arc a is about 5 degrees, the zero, or 
point of horizontal position being placed 3 degrees from the upper ex¬ 
tremity. The chief use of this arc was to determine approximately the 
elasticity of the bars, and of the machine itself, as preliminary to that in¬ 
quiry. The weights W, in the scale-pan, (which, with its suspending 
chains, cross-bars, &c. weighs 56 pounds,) were, in every case, applied on 
the lever, at the third mark, a distance from the axis of motion 30 times as 
great as that between the axes of the two bolts, or 30 x 2.914=87.42 inches. 

Friction of the Machine. 

The amount of friction of the machine already described for testing the 
tenacity of metals, was an object requiring particular investigation before 
any thing more than a comparative value could be assigned to the results 
which were afforded by the experiments. 

To determine this point, it was deemed advisable to ascertain under va¬ 
rious loads what proportion the weight which was sustained by the machine, 
after it had been raised by the screw S till the index stood at zero on the 
arc a, bore to that which, after the lever was relieved and then loaded 
again with the same weight, would cause it once more to descend to zero. 

Between the heads b' and b" was placed a strong bar of iron 4 l inch wide 
by | of an inch thick. Two methods were then pursued for the purposes 
of mutual verification. 

1. A certain weight was placed in the pan suspended at h, and the screw 
S turned until, as before mentioned, it was raised to a level so that z stood 
at zero on the graduated arc. The windlass w was then employed to raise 
the scale-pan and entirely relieve the lever. On again restoring the 
weights, the index remained some minutes of a degree above 0, and an ad¬ 
ditional quantity of weight was necessary, to bring it once more down to 
that level. As, in ihis case the weight added served to increase the friction, 
it is manifest that the comparison of it with the whole weight, itself in- 


9 


eluded, must be necessary in order to show the relation between the weight 
at first raised and that part of it, which represented the friction of the ,ma- 
chine. When the weight was raised by the screw, the bar which con¬ 
nected the heads b' b ", must have sustained a strain composed of the 
weight raised added to the friction of the machine; whereas when the 
weight was let on by the windlass while the index was at some distance 
above 0, the bar sustained a strain represented by the weight borne, dimi - 
nislied by the friction. 

II. The lever was caused to rest on a solid support near the extremity, 
the index being opposite to zero on the arc, and in that position the scale- 
pan was loaded with the weight under which it was intended to try the 
friction. The screw S was then carefully turned to strain the bar and bring 
the loaded arm of the lever barely off of the support. The weights were 
next raised by the windlass and the recoil of the machine raised the lever 
to a certain elevation, from which it was once more depressed by replacing 
the weights upon it, and adding such an amount as would just depress the 
arm to the level of its original support. 

The first of the above methods gives the double , and the second the 
single , friction of the machine. The following table exhibits the weights 
in the scale-pan, the weight representing the friction when the first method 
was employed ; the same for the second method; and the ratio of the fric¬ 
tion to the total weight sustained by the lever. A correction is required 
particularly at the higher pressures, on account of the increased elasticity 
in the machine under the added weights, which actually brought the index 
down to zero sooner than it would have arrived at it, by the simple effect 
of a strain upon the lever regarded as inflexible. 

The machine was kept constantly well oiled, still a trifling difference 
may possibly have existed in regard to its condition at different times ; but 
no influence of this sort, was ever found sufficient to determine the rupture 
of a bar, after the weight had been taken up, the gudgeons newly oiled, and 
the same weight replaced, which it had borne previous to that operation. 


TABLE I. 




Double 

Friction. 


Single Friction. 

No. of the expe¬ 
riment. 

Weight applied 
to the lever. 

Weight requir¬ 
ed to counterpoise 
the double fric¬ 
tion. 

Ratio of friction 
to weight by the 
method of double 
friction. 

No. of repeti¬ 
tions furnishing 
the mean result on 
double friction. 

Weight requir¬ 
ed to counterpoise 
single friction. 

Ratio of friction 
to weight by the 
method of single 
friction. 

No. of repeti¬ 
tions furnishing 
the mean result on 
single friction. 

1 

56 

6.00 

.050+ 

3 

3.00 

.050+ 

1 

2 

112 

10.82 

.0514- 

7 

5.79 

.051 + 

6 

3 

168 

17.62 

.052-4- 

4 

9.06 

.051+ 

4 

4 

224 

24.85 

.0554- 

10 

12.75 

.053— 

5 

5 

280 

28.16 

.0504- 

6 

14.71 

.050— 

7 

6 

336 

35.30 

.053-f- 

5 

17.25 

.049— 

6 

7 

392 

38.33 

.0474- 

4 

20.42 

.050— 

4 

8 

448 

42.50 

.0484- 

4 

22.64 

.048+ 

7 

9 

504 

45.50 

.045+ 

1 

26.80 

.050+ 

7 

Mean .050 

Tot. 44 

Mean 

.050 5 

Tot. 47 


From the above table it appears that the second method gave results 
more nearly in accordance with each other than the first, but it will also be 
noticed that forty-four observations with the first gives a mean value sensi- 





























10 


bly identical with that obtained from forty-seven experiments with the se¬ 
cond method of trial above described. We were hence led to adopt 5 per 
cent, of the weight as the effect of the friction of the machine. The bolts 
are of well polished steel and the lower bearing of cast iron, and the upper 
one or the eyes of the straps i", i", of wrought iron. 

This relation of friction to pressure between these substances as deduced 
from the experiments of the committee, will be found to correspond very 
nearly with that obtained by Mr. Wood when operating on railway car¬ 
riages.* 

Elasticity of the Machine. 

In order to determine, in particular cases, the amount of elasticity 
exhibited by the bars under trial, it became necessary to ascertain the 
elasticity of the machine, when loaded with different weights. Several series 
of trials were accordingly made expressly with a view to this object. 

Putting into the machine, in place of a bar to be broken, one which was 
intended not to yield sensibly to the strains applied, and not in any case to 
be permanently elongated by them, different weights were appended to the 
lever, and allowed to remain until the latter had become stationary. They 
were then carefully raised by the windlass, and the lever allowed to rise by 
the recoil until it became entirely free from strain. The number of degrees 
and minutes on the arc a , traversed by the index, was then noted; the weight 
replaced, and the trial repeated until it was ascertained that no error of obser¬ 
vation had occurred. 

Three series of operations were performed each beginning with the lever 
3°. 30' above zero, when entirely unloaded, but fully in contact with its 
bearings. Weights were then added by 56 pounds at a time, and the de¬ 
pression below 3°.30', produced by each addition, was noted. This was 
continued until weights had been added sufficient to bring the index to 0, 
which was effected with 11 weights of 56 pounds each. 

If the lever had been entirely inflexible, the natural sine of the angle of 
elevation after being relieved might have been considered the measure of 
the compression of parts sustained by the frame, links, &c. under each 
weight; for as the shorter arm of the lever is only 2.914 inches in length, 
while the bar and connecting straps are more than 5 feet, the direction of 
the horizontal bar may be considered sensibly constant. 

The following table contains the results of the experiments just described, 
together with those of another set in which the operations were in every re¬ 
spect similar, except that the weights were applied by 37s pounds at each 
time instead of 56 pounds. The natural sines are added, by comparing 
which with the respective compressing forces, it will be found that the law 
which governs the elasticity of the machine is, that the latter is proportion¬ 
ate to the fifth root of the cube of the compressing force. 

* See Wood on Railways, Smith’s edition, Philadelphia 1832, p. 202. The 
mean of nine out of twelve experiments there detailed is exactly 5 per cent, for the 
riction between steel and cast iron. 


11 


TABLE II. 



•3 
£ , 





•2 

N 

to 

3 s 

5 . 

4i <3 

.5 * * . 



c 

•«** bo 
to c 

JJ-N N 

©«to 

^ 3 


REMARKS. 



^>■5! % 

^ £ £ 

Recou 
in min 
gree. 

►5 13 
< v 5 

**«. **o 
to to to 



1 

37.5 

40/ 

.0116353 

Comparing the first with the last experi- 

2 

56. 



ment by the formula / 61 nat * 

sin. 211.5' 

47.2 

.0136713 

\37. 5f nat. 

sin. 40 7 





we get #=0.594. 


3 

75. 

58. 

.0168707 

The 3d and 16th, by a similar comparison, 




give #= 

0.608. 

4 

112. 

74.7 

.0218149 

The 4th and the 19th give #= 

0.606. 

5 

150. 

86. 

.0250138 


6 

168. 

95. 

.0276309 

The 6th and 8th give #= 

The 7th and 17th give #= 

The 8th and 10th give #= 

0.600. 

7 

187.5 

100. 

.0290847 

0.627. 

8 

224. 

112.7 

.0328644 

0.595. 

9 

262.5 

120. 

.0348995 



10 

280. 

128.7 

.0375158 

The 10th and 12tli give x= 
The 11th and 18th give #= 

0.560. 

11 

300. 

134. 

.0389692 

0.641. 

12 

336. 

143.4 

.0415850 


13 

375. 

154.5 

.0447818 

The 13th and 15th give x— 

0.583. 

14 

392. 

157.4 

.0456536 


15 

412.5 

166.3 

.0482687 



16 

448. 

171.9 

.0500119 



17 

504. 

186. 

.0540788 

The 2d and 17th give #=0.625 

Mean 0.603 

18 

560. 

199.7 

.0581448 

Hence the mean of the above 10 compari- 

19 

616. 

211.5 

0613389 

sons gives #=.603, which, by rejecting the 


last figure, furnishes the law above stated. 


Another set of trials was made, loading the lever with weights by 7 
pounds at a time from 0 to 609 pounds; and from the results of this and the 
preceding series a table was constructed, furnishing the column of elastici¬ 
ties of the machine for every observed depression under given weights 
when testing the elasticity of bars of iron. By deducting the elasticity due 
to the machine alone from that obtained by observation, we get the mea¬ 
sure, in minutes of a degree, of the elasticity of the bar. 

In the table of elasticities actually observed will be found various num¬ 
bers between 5' and 73'. To facilitate the comparison of each observed 
elasticity with the length of the bar on which the trial was made, the fol- 
lowing table is annexed in which the natural sine belonging to each num¬ 
ber of minutes has been multiplied by 2.914, the length in inches of the 
shorter arm of the lever. 














12 


TABLE III. 


Observed elasti¬ 
city in parts of the 
arc. 

Corresponding 
extension and re¬ 
coil of the bar in 
inches. 

Observed elacti- 
city. 

■Extension and 

recoil in inches. 

Observed elasti¬ 

city. 

Extension and 

recoil in inches. 

Observed elasti¬ 

city. 

Extension and 

recoil in inches. 

Observed elasti¬ 

city. 

Extension and 

recoil in inches. 

5' 

.0042323 

19' 

.0160829 

33' 

.027965 

47' 

.039835 

61' 

.051695 

6 

.0050788 

20 

.0169295 

34 

.028821 

48 

.040680 

62 

.052539 

7 

.0059253 

21 

.0177760 

35 

.029665 

49 

.041529 

63 

.053385 

8 

.0067718 

22 

.0186525 

36 

.030508 

50 

.042370 

64 

.054230 

9 

.0076183 

23 

.0194690 

37 

.031360 

51 

.043223 

65 

.055076 

10 

.0084648 

24 

.0203455 

38 

.032200 

52 

.044060 

66 

.055920 

11 

.0093114 

25 

.0211618 

39 

.033050 

53 

.044903 

67 

.056792 

12 

.0101579 

26 

.0220083 

40 

.033839 

54 

.045750 

68 

.057639 

13 

.0110041 

27 

.0228548 

41 

.034769 

55 

.046596 

69 

.058484 

14 

.0118506 

28 

.0237013 

42 

.035580 

56 

.047439 

70 

.059330 

15 

.0126972 

29 

.0245478 

43 

.036425 

57 

.048288 

71 

.060173 

16 

.0135437 

30 

.0253941 

44 

.037270 

58 

.049158 

72 

.061019 

17 

.0143902 

31 

.0262406 

45 

.038115 

59 

.050009 

73 

.061865 

18 

.0152367 

32 

.0270871 

46 

.038989 

60 

.050848 

74 

.062710 


Instead of the numbers in the table, a tolerably near approximation to the 
true temporary elongation corresponding to each observed elasticity of the 
bar in minutes might have been obtained, by multiplying the number of 
minutes by .000847 inch, the length of one minuie on the arc of a circle, 
the radius of which is 2.914 inches. This would give a result sensibly 
correct, especially for all numbers of minutes under 60. 

Sources from which the materials were obtained. 

The materials on which the committee have performed the experiments 
detailed in this report, were procured from various sources, a considerable 
quantity having been collected previous to their appointment by one of its 
members, then making arrangements for a private course of investigations 
on several scientific and practical points, relating to tenacity. Other specimens 
were voluntarily offered, or kindly supplied at the request of the committee 
by the different manufacturers, or other persons to whom application was 
made for that purpose. In several instances, more specimens of the same 
iron were furnished than will be found mentioned in the tables as derived 
from the same quarter;—the whole number obtained being about two hun¬ 
dred and fifty, and the number tried about one hundred and fifty. As the 
aim of the experiments was the establishment of such practical truths as 
might be found generally useful in regard to the manufacture and employ¬ 
ment of materials for steam boilers, it was not deemed necessary to enter 
into a minute comparison of the merit of different manufacturers from 
whom the materials were received, nor to limit the inquiry to any given 
number of specimens or of trials on those derived from each source. The 
reader, will, however, be able to institute such comparisons as his curi¬ 
osity may dictate,—the tables furnishing all the facts, (as well as the 
names of the manufacturers when known,) which have been obtained 
by the committee, in regard to the origin and manufacture of the different 
specimens. 




























13 


Among the names of those from whose manufactories specimens have 
been received, are Messrs. Mason & Miltenberger, H. S. Spang & Son, 
Barnet Shorb, H. Blake & Co. and Shoenberger & Son, of Pittsburg ; 
S. E. H. & P. Ellicott, and E. T. Ellicott & Co. of Baltimore; the 
Salisbury Iron Company, of Salisbury, Connecticut; Messrs. Yeatman & 
Woods, of Nashville, Tennessee; Mr. Massey, of Maramec, Missouri; R. 
Lukens, of Coatesville, Chester county, Pennsylvania; George Pennock, 
McWilliamstown, in the same county; Messrs. Grubbs, Lancaster county, 
Pa.,|HARDMAN Phillips, Esq., Clearfield county, and Messrs. Valentine & 
Thomas, Centre county, Pa. To Messrs. A. & G. Ralston the committee 
were indebted for specimens of boiler, bolt, and railroad iron, of English 
manufacture, which served as means of comparison between the foreign 
and the domestic material, and from other importers they procured those 
of Russian and Swedish manufacture, for the same purpose. All the 
samples of American iron thus far mentioned, were manufactured by the 
aid of charcoal. A single specimen furnished by Mr. P. Ritner, of Cart- 
house’s Place, on the West Branch of the Susquehanna river, was made by 
smelting with coke. 

The specimens of boiler copper, tried by the committee, were obtained 
from the establishment of John M’Kim, jr. & Son, of Baltimoie.—To the 
above, and several other gentlemen who were active in procuring the ma¬ 
terials, and otherwise forwarding the objects of this inquiry, the committee 
are bound to offer their grateful acknowledgments. 

Preparation and gauging of the specimens. 

The experiments were made on materials in several different forms, and 
as the results are in some measure dependent on the circumstances now 
referred to, it seems proper to describe those several conditions, together 
with the method of obtaining the areas of transverse sections at the points 
of fracture. 

As the greater number of experiments was, of course, made on materials 
manufactured expressly for steam boilers, the mode of preparing these is of 
most importance. The strips were in general cut, by shears, from the 
plates, about 2 or 2\ feet long, and 1 inch wide; and with a view to 
determine the tenacity in different directions, they were cut either length¬ 
wise, crosswise or diagonally of the direction in which the plate had been 
rolled. 

The tables will be found to indicate, in all cases where rolled iron is under 
consideration, the direction of the slitting. 

On specimens of this kind, trials were made in three ways. First , by 
finding and measuring the area of the smallest section, as the strip came 
from the shears, and placing it in the machine, applying force till that or 
some other section gave way. When not broken at the smallest section, 
the actual area of the point of fracture was ascertained approximately by 
measuring, after fracture, at a short distance on each side of the broken 
part, taking care to keep just outside of the constriction or part sensibly 
diminished by the strain. After thus determining the area previous to trial, 
a portion of the bar was replaced, and other fractures made, until the speci¬ 
men had been used up. Fractures on bars, tried in this manner, are referred 
to in the tables as made at original sections. But as the slitting of bars 
in the manner described necessarily caused some diminution of strength 
along the edges, and as from accidental causes this diminution was often 
very unequal, it was apparent that the irregularity in the strength migli 


14 


frequently be greater than that in the breadth of a strip. To ascertain the 
mean effect of the shears on bars of this breadth, the second method of trial 
was adopted. 

This consisted in filing away a section of the metal on each side of the 
strip, in the form of the segment of a circle. At different points, these 
sections were filed to different depths, with a view of ascertaining how far 
beneath the surface the metal had been affected. The scale of oxide was 
also in some cases filed from the surface, but in most instances where the 
rolls had left the iron tolerably smooth, it was thought best to take the mea¬ 
surements of thickness, as they must be taken in practice with the surface 
in its natural state. In some instances, it will be found that the fractures 
did not occur in the filed section, even when a considerable portion of the 
whole material had been filed away, (see bars 206 and 207, &c., table LII.) 
In general, however, about g of the breadth of the bar being removed by the 
two opposite sections, the sound part of the metal was attained, and gave 
results nearly proportionate to the areas of the remaining sections. 

But as neither the rolling nor the hammering of iron can give a perfect 
uniformity of structure, and as consequently the results on very deeply filed 
sections would not always prove uniform in their indications of strength, it 
became necessary, in order at once to remove the irregularities proceeding 
from the slitting, and to compare the advantage of different modes of manu¬ 
facture, and different kinds of metal employed, as well as to ascertain the 
maximum and the minimum strength of the same bar at various tempera¬ 
tures, to employ the third method of preparation, that of filing away the edges 
of the inch bars till they were reduced to f of an inch in width throughout 
their whole length, and also removing completely the scale from both faces, 
and rendering the thickness as nearly as possible uniform throughout. The 
bars treated in this manner were next divided through their whole length 
into spaces of one inch each, marked across with a steel point, numbered 
at every inch, and subsequently gauged at every mark, both in breadth and 
thickness. In these measurements, as well as those applied in the two other 
methods of preparation, the gauging was carried to thousandths of a lineal 
inch in both directions, giving the areas, true to millionths of a superficial 
inch. Plate II represents the apparatus used for this purpose, and a portion 
of a bar prepared for gauging. C is a pair of proportional callipers of 
brass, pointed at a , a , with steel. S is a screw head projecting 3 an inch 
above the face of the instrument, and is 5 of an inch in diameter, being a 
triflle less in length than the thickness of the two arms of the callipers. The 
distance S t is ten times that of S a, so that the space beween the points «, a, 
is read into tenths, hundredths and thousandths, when that between t , t, on 
the diagonal scale D, is found in inches, tenths and hundredths. 

Specimens of hammered iron and of iron formed into bars by rolling and 
slitting were tried with a view to certain comparisons and in these cases all 
the three modes of preparation applied to specimens of boiler iron were 
likewise employed. In a few instances specimens were received from the 
manufacturers in a form which required no alteration before trial, but in the 
majority of cases they were to be either slit or hammered and filed to adapt 
them to the purpose of these experiments. In the treatment of boiler-iron, 
heating before trial, was, with few exceptions, avoided. The tables will be 
found to contain a few experiments on upsetting, annealing and hammer¬ 
hardening. They will also exhibit a very limited number of trials on cast 
iron and steel, but as these materials enter sparingly into the composition 
of steam boilers, and as their tenacity has been formerly much more exten- 


Proportional CaUij 

































































































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Flute m 






















































































































































































































'«v 


Plate Ill. 



















































































































































































































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15 


sively examined than that of boiler-plate, it was not considered within the 
purpose of the present investigation to do more than present a few verifica¬ 
tions of the correctness of those results on which practical men commonly 
rely. 

The bars of cast iron were tried as they came from the mould, or with 
very little filing to remove the irregularities of the surface. The specimens 
of copper were all reduced by filing to a good degree of uniformity, and 
gauged as already described. 

At the foot of each column of original areas in each bar gauged through¬ 
out its length, will be found the mean area, and under areas of “ sections of 
fracture” are the mean areas of the points broken. 

Apparatus for High Temperatures. 

The general arrangement of the parts of apparatus expressly designed for 
experiments, at the highest temperatures, is presented in plate I., where F is 
the portable furnace for charcoal, suspended by an iron ring which is fastened 
on near its upper edge, and attached by means of pins on the opposite sides, 
to the two ends of a semi-circular fork on one arm of the lever x. The 
weight of the furnace and its contents is counterpoised by the weight c. 
About the centre of the lever is a slit, 6 or 7 inches long, through which 
passes the end of a screw suspending-rod. The nut belonging to this screw, 
is furnished, on its upper surface,with an elevated ridgq, serving the purpose 
of a knife-edge, which applies at pleasure to any one of several transverse 
notches on the under side of the lever along the slit This serves, for the time, 
to fix the lever and to prevent its sliding endwise unless when lifted from 
its bearing. 

As this nut revolves freely on the screw, a horizontal motion about the 
screw as an axis is readily given to the lever, while, to raise or lower the 
furnace in order to regulate the temperature, the knife-edge on the nut affords 
ample facility. The top of the furnace rises between the two guide-rods s, 
s, and between the two iron blocks b' and b" within which the bar to be 
tried, is confined. When not in immediate use, the furnace is swung round 
beneath the beam of the frame M, and placed under the cap H, the pipe of 
which is supported on the end of the crane R, adapted for its reception, 
and passing into a chimney at g. The Thermometer /, suspended from an 
arm projecting beyond one of the uprights which support the pulley p, is 
lowered, when in use, into a bath of hot liquid through which the specimen 
under trial passes, as described below. The details of the arrangement are 
seen in plate 111., where a plan is given of so much of the machine as may be 
necessary to comprehend the manner of fixing the bars and of applying 
the heat. In plate IV., a vertical section through the length of the bar, is ex¬ 
hibited; the references in both these plates, being, so far as they apply to com¬ 
mon objects, the same as those in plate I. Thus in plates III. and IV., i', i' and 
i ", i ". are the straps of iron connected with the blocks b' and 5", which by 
means of their projecting arms repose on the two guide-rods s, s. F is the 
furnace, t the thermometer seen immersed in the bath of hot liquid B, and x 
is the lever supporting the furnace. The bath is composed of an elliptical 
copper or sheet iron cup, 4\ inches long, 3£ wide, and 4 inches high with 
two lips or channels, in the direction of its shorter diameter, each one inch 
deep, and the same in breadth, to admit the passage of the bar through them, 
and to contain the packings w, w, adapted to retain the hot liquid, and cause 
it to cover the bar a. These channels extend each about one inch beyond the 
sides of the cup, affording room for the straps y , y, passing beneath them 

2 


16 


and rising on each side, near the tops of which are placed two cross-heads, 
c, c, and through these pass the tightening screws n, n, employed in press¬ 
ing down the packings w, w. The manner in which the bars are held by 
the blocks b\ b", is seen at w , w\ where the dove-tailed form of the holes 
into which the wedges pass and the arrangement of teeth on the steel face 
of each wedge, are particularly indicated. In adjusting the bars in their 
place for these experiments, it became necessary to form perfectly secure 
joints at w , w , where they pass through the channels before mentioned. In 
most of the experiments below 600 degrees this was effected by means of 
loosely spun cotton, wrapped about the bar, for an inch at each point where 
the screws were to be applied. For temperatures above 600° a packing 
formed of fibres of iron scraped from wire in the manufacture of weavers’ 
reeds was adopted. This being formed into mats, and rolled in a powder 
of oxide of tin,—constituted an impervious barrier to the melted metal, par¬ 
ticularly after being duly settled and condensed into place, and then firmly 
compressed by the screws. 

Below 600°, the fluid commonly employed was olive oil, and for higher 
temperatures a mixture of tin and lead. In some cases, however, between 
the melting point of tin and the highest temperatures applied, the latter metal 
only was used. 

The source of heat for moderate temperatures was either a single or a 
double-wick spirit lamp, of Dr. Mitchell’s form. When the latter proved 
inadequate to supply the desired temperature, the furnace of charcoal F was 
substituted, and, by means of notches o, o, at its upper rim, it was raised so 
high as completely to embrace the bath B as represented in plate IV. 

Standard of High Temperatures. 

The standard of temperatures below the boiling point of mercury was 
the mercurial thermometer. Above that point the instrument adopted by 
the committee, was the steam pyrometer described in the American Journal 
of Science vol. xxii. page 96, by Prof. W. R. Johnson. At S, plates III. and 
IV., is the standard piece of wrought iron laid horizontally beneath the bar 
a, and kept in its place by the buoyancy of the mixture of tin and lead, the 
superior density of the latter metal serving to float the iron, and the higher 
specific heat of the former, keeping the temperature of the bath more 
steady than it would have been iflead alone had been employed. 

As several improvements have been made in this pyrometer since the date 
of its first publication, which are conceived to be important in point of ac¬ 
curacy and despatch, it is proper that we should present a view of its struc¬ 
ture as used in these experiments, together with a concise statement of 
the mode in which the latter were conducted. 

The instrument is founded on the supposition, that from a mass of water 
already in ebullition, a weight of vapour may be generated, by immersing a 
solid, of known weight and capacity for heat, which shall be proportioned 
to the temperature of such solid above the boiling point of water. In this 
supposition it is, of course, implied that the specific heat of the solid is con¬ 
stant, or that we allow for its variations ;—that during the experiment no 
heat is received by the water from any other source than the hot solid im¬ 
mersed, and also that vapour ceases to escape, as soon as the solid has been 
cooled, by vaporization, from the initial temperature, down to that of 
boiling water. It is further requisite that no heat from the immersed solid 
be expended in any other way, than the production of vapour by passing 
from a sensible to a latent state. A convenient apparatus for ascertaining 


17 


the weight of vapour thus expelled by the hot body, used as a standard 
piece, is another requisite. 

In almost all the usual processes of weighing, the time occupied in making 
an adjustment of the counterpoise, is too considerable to admit the supposi¬ 
tion that no loss of vapour from an open vessel of hot water would take 
place, between the time when the solid attains the boiling point, and that 
when the equilibrium would be reproduced. To answer the conditions above 
indicated, the steam pyrometer is constructed in the form represented in 
plate V. A is a cylindrical boiler, 12 inches high, constructed of two con¬ 
centric cylinders of tinned sheet iron, between which is a stratum n, n, half 
an inch thick, of dry charcoal-dust, (lamp black,) to serve as a non-conduc¬ 
tor and preserve the water within, from loss of heat by radiation during the 
experiment. 

The bottom is formed of a single sheet of the same metal connected with 
the lower edge of the inner concentric cylinder, and rising in the form of a 
segment of a sphere to the height of £ of an inch, in order to present an en¬ 
larged surface to the action of the lamp L, which keeps the water in ebulli¬ 
tion until the moment when the solid is immersed, t is a thermometer bent 
at right angles £ of an inch from the bulb, and passing along a tube opening 
into the boiler. A packing around this part of the stem prevents leakage, 
and the bulb being wholly immersed in the water, serves at all times to indicate 
its temperature, and particularly to mark the moment when that of the solid 
has descended so low as to cease generating steam of atmospheric tension. 

Mode of ascertaining the weight of vapour expended. 

The mode of suspending the boiler to the beam of the balance, is seen at 
m where the dotted prolongation of the beam B forms a forked curve rather 
greater than a semicircle, each extremity of the arc ra, m, (Fig. 2.) being 
turned inward so as to stand at right angles to the direction of the beam; 
this brings the two bearing edges which support short hooks attached to 
loops on the opposite sides of the boiler, into the same line parallel to the 
main axis or knife edgef, at the central part of the beam. These parallels 
are exactly 12 inches apart. The opposite arm of the balance beam is cy¬ 
lindrical, and cut into a fine threaded screw to within an inch and a half of 
the fulcrum f , where the beam is divided for a certain space into two por¬ 
tions (x x , fig. 2.) between which passes the upright rod of the supporting 
stand. The beam used during a considerable part of the experiments con¬ 
tained 150£ threads in one foot of the length of the screw, and was £ an 
inch in diameter. At the highest temperatures which the committee had 
occasion to measure, the number of threads passed over in one experiment, 
did not exceed 11^ or so much as to measure from 1100, to 1200 degrees 
of temperature. 

By a eareful measurement of different numbers of threads, selected at va¬ 
rious parts of the screw-arm, (which was 16 inches long) it was ascertained 
that, though at the two extremities, the threads differed slightly from their 
mean length, yet at the middle portion, where the revolving counterpoise P 
is represented in the figure, no appreciable difference could be detected, and 
as this was the part always occupied by the weight, the instrumental error 
from this source may be consideied altogether unimportant. In fact the ex¬ 
tremes of the variation just referred to taken most unfavourably, could not 
have in the highest temperatures, amounted to more than 7 degrees Fah., 
which at points so elevated as 13 or 1400 degrees, would not be deemed a 
very important inaccuracy. 


18 


But even this was avoided by occupying that part of the screw where the 
threads were of equal length ; and by making an adjustment of the balance 
and weighing any given body placed on the boiler, with the counterpoise 
in different parts of the range selected for the experiments, it was easy 
to verify the accuracy of the measurements and determine precisely the 
error, if any had existed. But this method when tried, only served to con¬ 
firm the result of the other. 

The revolving counterpoise. 

On the screw already described, was placed a revolving counterpoise P, 
which, together with its index I, placed on a neck projecting beyond the 
base of the cylinder, weighed 10517 grains ; consequently, as each thread.ol 
the screw measured 0.07872 of an inch, the motion of the counterpoise 
over one thread was equivalent in effect to a weight of 100 grains applied 
at that end of the beam where the boiler is suspended, or T -i^. part of a re¬ 
volution marked a difference of one grain in the weight of water in A.* 


* The method used in determining, by calculation,*the true adjustment of parts and 
the graduation of the scale of the steam pyrometer is equally applicable, whatever 
may be the length of the weighing beam, or of the threads of the screw, and what¬ 
ever the nature of the material employed for a standard piece, the latent heat of 
vapour, the kind of liquid from which it is produced, or the scale of thermometer 
to which we refer the indications, marked on the revolving counterpoise. 

Thus if L be the length of the arm from / to m where the boiler is suspended, and 
? 2 =the number of threads of screw on an equal length of the opposite arm; then 

—=the length of a thread. 
n ° 


Putting P=the weight of the counterpoise, 

and r=the weight of vapour which must escape in order that an equilibrium, de¬ 
stroyed by its loss, should be restored by making P move one revolution, that is 

L PL P 

one thread nearer to f, we shall have _ : L : : v : P or — —Lv ,* whence v= —. 

J n n n 

This may be termed the mechanical relation of the instrument to the vapour pro¬ 
duced. 

To determine the physical action of the standard piece, if z be supposed=its 

specific heat; /= the latent heat of vapour from the liquid at its boiling point; 

i = the weight of the standard piece (expressed in the same denomination as that 

of P ); t= the number of degrees to be placed on the circumference of the revolving 

weight; P=the degrees belonging to the same scale as those in which l is expressed; 

and t? = (as before,) the weight of vapour counterpoised by a single revolution of 

P; then the efficient cause of vaporization while the standard piece cools through t 

degrees, will be represented by itz, and the effect produced must be expressed by vl ; 

• • • • itz • 

Hence is derived the equation lv= itz , or v= — Comparing this value of v with 

P itz l 

that obtained above, we get —__— Hence the weight of the standard piece = i 
PI ^ l 

and the five following formulas will give either one of the other quantities, 


ntz. 


when the rest are assigned, viz. P = 


nitz 


PI 


nitz 


l 




nit 


-jf. In practice it was found most convenient to make t 


PI , PI , , 

n = —; t — — and l = 

itz niz , 

100° Fah. But by 


assuming t equal to the distance between the freezing and the boiling point of water 
under mean atmospheric pressure, a single standard piece would be sufficient to 
render the instrument universal in its indications. The curved surface of the re¬ 
volving weight would only require to be divided into as many separate bands as 
there were different scales to be placed upon it, and graduating each band into as 
many equal parts as the particular scale comprehends degrees between the two 




STEAM' PYMMETEM 


Fla/, V. 




1— 1| 

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ilPi'rl 1 3 

gyi 

1 — 



(jfli k. 


Wm. Mqjoti Del 



























































































































































































19 


The standard piece employed to produce vapour after having been heated 
in the bath of melted metal surrounding the bar under trial, was formed of 
wrought iron of the figure seen at S, its greatest length 2| inches, its 
diameter one and Ag- inch and its weight 6336 grains Troy. This was sus¬ 
pended by an iron wire of an inch in diameter to the centre of a wire- 
gauze cap w , the lower and smaller end of which, entered the mouth of the 
boiler A, at the base of the funnel r. The upper diameter of this cap is 2£ 
inches and its height 2| inches, giving an area, including the top and sides, 
of more than 13| square inches, or more than three times as much as the section 
of the boiler at its mouth. The object of employing this cap is to prevent 
the dashing out of water by ebullition—an effect which is, however, only liable 
to happen near the close of an experiment when the iron has descended to 
the temperature of maximum, vaporization ,* and when the boiler contains too 
much water. 

The Condenser. 

In order to prevent all escape of vapour after ebullition has ceased, a 
cylindrical cap of tinned iron D, is placed over that of wire gauze, the in¬ 
stant that the boiling point is attained. In general, this cap is kept suspen¬ 
ded at one side of the boiler A, as exhibited in outline at D'. The lower 
rim of the condenser is furnished with an exterior welt or hem of silk, 
sewed to the tin by means of fine punctures near its edge (This serves 
effectually to prevent the escape of steam, and, besides allowing the operator 
to attend deliberately to the adjustment of the counterpoise, will admit, when 
necessary, the postponement of this process fora considerable length of time. 
The counterweight c, is to balance the standard piece S, with its suspending 
wire, and the wire-gauze cap VV. As long as the water is kept boiling by 
the action of the lamp L, C is removed from the beam and is replaced only 
after the condenser has been transferred from D' to D. The support E of 
the beam may be elevated or depressed on its sustaining rod by means of the 
tightening screw K. Immediately below the fulcrum f, is a small hole 
drilled horizontally into E, to receive a brass tap carrying a ball § of an 
inch in diameter, through which passes the small index-wire i, so adjusted 
by means of the screwed counter weight c, as to be accurately balanced on 
the tap g , as an axis on which it turns with no other resistance than what 
is due to the friction produced by its own weight. 

Near the extremity v of this wire, it is bent at right angles, and the 
pointed extremity directed to the side of the beam where, at o, is a straight 
line | of an inch long, serving to guide the eye in reproducing the level 
after an experiment. A little below this line, is a transverse hole through 
the beam, in which slides the register s (Figs. 1 and 2,)—a wire about Ag. of 
an inch in diameter, and 2£ inches long. While the water in A is kept 
boiling by means of the lamp, the boiler continues to rise, and as the regis¬ 
ter now projects out beyond the index i, it lifts the latter, keeping the point 
v always directed a very little above the line o. But when W has been in¬ 
serted in its place, with S suspended in the water, the additional weight, 
destroying the equilibrium, depresses the boiler, the base of which rests on 

points above mentioned. Thus we should have on the band marked Reaumer, 80 
degrees; Centigrade, 100°; Delisle, 150°; and Fahrenheit 180.° It may not he 
improper to remark that in applying the above formulas, the numerical value of l 
must also vary with the thermometrical scale. Thus if for Fah. it be 1037° it 
will be for Centigrade, 576*; for Delisle, 8634, an d for Reaumer 4G0|.. 

*See Amer. Journal of Science, vol. 21, p. 304. 

o * 


20 


the flat surface of the lamp L, the concavity in the bottom serving as an 
extinguisher to the flame. The index i, is, in the mean, time left at the 
level attained by the register at the moment before the immersion. While 
ebullition is proceeding, the operator pushes back the register so as to 
project but little from the interior side of the beam ; then observing the 
thermometer t , takes the condenser from the position D', and, at the instant 
the ebullition ceases, covers the boiler with it, as at D, letting the standard 
piece remain in place; and having attached the counterpoise C, proceeds to 
bring down the boiler end of the beam, (which at first rises above the index 
i ,) by causing P to revolve in the direction towards /. 

The number of revolutions being counted so many hundreds of degrees, 
he has only to add to their number 212°, in order to obtain at once the tem¬ 
perature by Fahrenheit’s scale. 

As both the latent heat of vapour and the specific heat of iron enter into 
the calculation, in constructing the steam pyrometer, and as on both these 
points considerable discrepancy prevailed among writers who had treated 
of these subjects, it was thought important to attempt a direct solution of 
the question as presented in the particular case of this investigation. 

Two methods offered themselves, of verifying the calculations respecting 
the instrument. The first was, to heat the standard piece to any known tem¬ 
perature above 212°, and in that state plunging it into the boiling water to 
ascertain whether the amount of water vaporized weighed as many parts 
measured by hundredths of a revolution of C, as the standard piece had been 
heated in degrees above the boiling point. 

This method being the most direct, was first resorted to by the com¬ 
mittee. 

As the standard piece S, was at first made one or two hundred grains 
heavier than was supposed to be necessary, trial was made in the way just 
indicated, and as an excess of vapour was found to have been obtained, the 
standard piece was proportionally reduced in weight to that which has been 
already stated. 

The other method consisted in determining separately by direct experi¬ 
ment, both the latent heat of vapour, and the specific heat of the standard 
piece. The researches on these subjects were made in the manner and 
with apparatus described below. 

Specific heat of iron. 

In determining the specific heat of the standard piece of the steam pyro¬ 
meter it was deemed adviseable to employ processes somewhat independent 
of each other, and especially to vary the circumstances of the experiments, so 
that if possible the discordances on this subject might be reconciled, or 
at least referred to their probable origin. The first step was to ascertain 
the specific heat of the standard piece from 212° to the ordinary temperature 
of the atmosphere. 

Bath for heating the standard piece. 

The apparatus for this purpose is represented in plates YI. and VII. In plate 
YI. is seen a vertical section of the apparatus in which the iron standard piece 
S was heated. W is a cast iron vessel in the form of a frustum of a cone, 
12 inches high, 7 inches in diameter at top, and 5 at the bottom ; the upper 
edge being furnished with a flanch to match a corresponding flanch on a 
cover D, which was turned to fit it, and to form with it a steam tight joint 
as at/,/,. In the central part of this cover is the mouth of another vessel 
or tube M, 2| inches in diameter, the bottom of which is about £ an inch 


. " iVi _ - '• aSt --IT .y /• 



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WR. Johnson 

















































































































































21 


above the bottom of W. The space between the outside of the tube M and 
the inside of W, is nearly filled with water, as seen at w , w, introduced by 
an aperture ordinarily closed by the iron stopper P. The interior of M 
is filled to about the level ra, m, with mercury. 

In the cover D on the side opposite to P, is another aperture into which 
is fitted by grinding, an iron tube G, to receive and convey away to a water 
vessel I, the excess of vapour generated in W. The vessel thus constructed 
is placed in a circular opening in a sheet iron plate, B B, 14 inches square, 
which rests on two guide rods R, R, of the frame of the machine. (Plate, 1.) 

F is the furnace already described, as applied to the purpose of heating 
the bars of iron. X is a sheet iron cylindrical case, 5 of an inch thick, 
open at both ends, and having along one side, a slit s s, of an inch wide 
left for the purpose of permitting the wire n, by which the standard piece 
S is suspended, to be introduced or withdrawn laterally, while the loop 
at its top is held by one hand of the operator; and by the other, the 
handle Y. The rod which carries this handle is fastened by rivetting to 
the inside of the case Iv, and below the rivets the point is turned inward to¬ 
ward the centre of the case, preventing the iron cylinder S from rising 
above that point. This gives the operator entire command of the latter, not¬ 
withstanding the buoyancy of the mercury. 

The thermometer T, graduated above the boiling point of water, was 
placed with its bulb on a level with the centre of S. 

By raising or lowering the furnace F, the ebullition was maintained at a 
nearly uniform rate during the time of several consecutive experiments. 

When the mercury in T was found to be stationary at 212°, the shield 
K was withdrawn from the mercurial bath ; the operator held Y in one hand, 
while the other supported the wire n ; and in this manner without allowing 
S to come in contact with the air, conveyed it to the mouth of the water 
vessel of the cooling apparatus, where K was held in a vertical position, and 
the wire quickly lowered till the standard piece was immersed, when the 
shield was immediately removed, the wire escaping through the slit s s. 

The cooling apparatus. 

The arrangement of parts in the cooling apparatus, is seen in plate VII., 
where A is the cylindrical containing vessel, filled with water to such a 
height as to be completely full, when the standard piece S, and the bulb of 
thermometer t are immersed. 

B is a cylindrical vessel of tinned iron, 14| inches high, and 9 inches in 
diameter, to which is adapted the cover D of the same material, having in 
the middle a circular aperture a «, 3 inches in diameter, for receiving the ther¬ 
mometer t , and the standard piece S ; allowing likewise sufficient space to 
move the suspending wire and thermometer. Another aperture through 
D, near its circumference, admits the lower part of the thermometer i, and 
an opening near the bottom of B, receives the bulb of the thermometer /. 

The thermometer 0 was suspended just without the vessel B, to mark 
the temperature of the room. C is a support for the water vessel A, formed 
of a cylindrical block of charcoal, 4 inches high. 

The method of adjusting the weight of water in A, in this series of ex¬ 
periments, w'as the same as that subsequently described in the experiments 
on the latent heat of vapour, except, that in the present case, no process of 
weighing was required, after the heating had been performed. 

The exact adjustment of the quantity of water to be used in every repetition 
of a given series, was made by means of a tube, of small dimensions, open 


22 


at both ends; by the aid of which it was easy to add or to remove minute 
quantities of liquid to render the balance true. 

Thermometer in the Water Vessel. 

The most important of the thermometers used in this part of the investiga¬ 
tion was that marked t , but which was in fact the thermometer A, elsewhere 
referred to, the bulb of which was 7l inches long, intended to reach from 
the top to the bottom of the liquid, and which, it actually did in some of 
the containing vessels, with which it was used. Its diameter was about £ 
of an inch. The glass constituting the bulb of this thermometer weighed 
433.85 grains, as ascertained by actual weighing, after the instrument had 
been broken. It was filled after the elongated bulb had been joined to its 
stem, and the separate weight of these ascertained. The mercury precisely 
filled the bulb alone at 32°, and the weight of mercury required for this pur¬ 
pose was found to be 4682 grains. As most of the experiments with this 
instrument were made with an initial temperature about 62°, it has not been 
deemed necessary to make more than one correction for the quantity of 
mercury expelled from the bulb, or excluded from the influence of the water 
vessel. At 62° the bulb must have held, by calculation,* 4670 grains 
of mercury, which by a mean of several determinations already published, 
possesses a specific heat of .0327, and gives an equivalent in grains of 
water, of 152.7. 

When this thermometer was used in connexion with a containing vessel 
of glass, the weight of its bulb was added to that of the vessel; and in other 
cases, the specific heat attributed to it, was that obtained by means of several 
trials of it with glasses of different thicknesses instituted with a view to deter¬ 
mine the effect of that material, towards cooling the heated body or stan¬ 
dard piece. The specific heat thus found was .10036, according to which 
the bulb would be equivalent to 43.45 grains of water. The length of the 
scale of this thermometer was 37 inches, and the graduation extended from 
34° to 74°; so that each degree was nearly of an inch in length and the 
degrees were divided each into 50 parts, each part being of such magnitude 
that the eye could, when necessary, easily subdivide and read them into 
hundredths. 

The graduation of this thermometer was obtained by direct comparison 
with a well tried standard instrument, the degrees of which were about £ of an 
inch in length. For this purpose, the bulbs of both were immersedin a large 
quantity of water contained in a Hessian crucible, surrounded by another of 
black lead; thus affording a combined mass which changed its temperature 
with extreme slowness, and enabled us to mark with deliberation and accu¬ 
racy every degree on the long scale, after having for some time agitated the 
two in contact with each other and tempered the water to the point re¬ 
quired. 

The general mode of operating with the apparatus, plate VII., was, after giv¬ 
ing the water vessel and thermometer t , a temperature a few degress below 
that of the surrounding air, to take simultaneous observations of all the ther¬ 
mometers which were recorded by one assistant, while another person 


* Petit and Dulong, found the expansion of mercury in glass between 32° and 

212 ,° to be —1— consequently its expansion for 1° s_ } _ 1 and for 

63 *8 180X63.8“ 11484 OA 

(62°—32°)= 30°, it will be T y4-g-T°f its bulk at 32°. Bat 4G82 X 30 — 

12.2 grains and 4682 — 12 = 4670 as above stated. 11484 







23 


bringing the hot standard piece, surrounded by its shield, from a distance of 
about 4 feet out of the heating apparatus (Plate VI.) immersed and held it 
suspended, as already described. The moment of immersion was observed 
by a second assistant, on a time-keeper marking seconds. The manipulator 
continually moving the thermometer t, and the standard-piece about in the 
water, read off the degrees and parts as successively attained by the mer¬ 
cury, while the second asssistant noted, and the first recorded them, together 
with the time of each observation. 

The method just described, afforded the means of determining approxi¬ 
mately, the proper temperature below that of the air, at which the water 
ought to be, when the standard-piece was immersed, in order that the heating 
and the cooling power of the atmosphere should be equal to each other. 
Table XIV. will be found to contain a synopsis of the experiments con¬ 
ducted in this mannner with reference to different containing vessels. Some 
trials were made to ascertain, with different vessels, the rate at which the 
air alone, would, under given circumstances, produce certain elevations or 
depressions of temperature. But the interference of extraneous causes, 
such as the presence or absence of a stove in the apartment, the heat de¬ 
rived from the person of the observer, and others near the scene of the ex¬ 
periment, made it evident that a good defence against the influence of the 
air would be a better guarantee against error, from that source, than any 
table of corrections which could be constructed amidst so many modifying 
causes. 

The results of a series of trials made in part without employing the vessel 
B to defend the water from the air and from radiation, are exhibited in Table 
IV. Some attempts were made, as above referred to, towards the correction 
of the irregularities therein observed; but the uncertainty attending the pro¬ 
cess, induced the committee to prefer, when practicable, the prevention , to 
the correction of these anomalies. As the vessel B held 924$ cubic inches, 
the whole quantity of air it could contain did not exceed 277^ grains; which, 
supposing the specific heat of air to be .26, would not be equivalent to 
more than 72 grains of water, but as a considerable portion, amounting to 
at least A of the whole, was occupied by the water vessel and its support, 
the remaining air could in no instance have been equivalent to more than 
62 grains of water, and as the greatest change which occurred in the tem¬ 
perature of this portion of air during any experiment, was but 1.7°, and as 
the mean of all the changes of this kind observed during the progress of the 
investigation, was a gain of 0.325°, while the correspondent mean gain of 
temperature in the water was 7.26°, and the mean weight of the latter 
13.100 grains, it is evident that the relative influence of the air and of the 
water will be represented by 62 grains X 0.325° = 20.1_5 and 13100 grains 
X 7.26° = 95106, or the former is part of the latter, from which it ap¬ 
pears that from this cause the expression for the specific heat could not have 
been affected under the fifth place of decimals. 

In a series of 13 trials in which the water, amounting to about 40,000 
grains, was contained in copper vessels, (Table VIII.) and the rise ot tem¬ 
perature in the same was at a mean about 2.5° the air gained about .292 of 
a degree, which would indicate that the cooling power of the air confined 
in the vessel B, compared with that of the water in A was but as 1 to 5550, 
a result which would still less affect the general correctness of the determi¬ 
nation. 

[The reader will please to observe that many of the following Tables ex - 
tend each over two opposite pages.'] 


24 


TABLE IV. Experiments to determine the specific heat of the wrought iron stand¬ 
ard piece used in experiments with the steam pyrometer employed in this investigation , 
the water being contained in a thin glass cylindrical jar , weighing 3325 grains, and 


No. of expe¬ 
riment. 

Date. 

Tempera¬ 

ture. 

Tempera¬ 

ture of the 
watei at the 

beginning-. 

Tempera¬ 

ture of the 
water at the 

end. 

Gain of 

tempera¬ 

ture by the 
water. 

Loss of 

tempera¬ 

ture by the 
iron. 

l ime taken 

up by the 

experiment. 

Weight of 

water in the 

jar. 

^Equivalent 

of vessel in 

grs.of water. 

Equivalent 

of thermom¬ 

eter in wa¬ 
ter. 

1 

1834. 
Nov. 22. 

o 

69. 

o 

64.5 

0 

69.8 

o 

5.3 

o 

142.2 

480" 

grs. 

19177.8 

grs. 

339 

grs. 

140. 

2 

Dec. 6. 

65.5 

59.5 

64.8 

5.3 

147.2 

400 

19788 1 

329 

143.3 

3 

u 

69. 

61.2 

66.5 

5.3 

145.5 

300 

19788.1 

339 

143.3 

4 

<( 

70.5 

64.15 

69.2 

5.05 

142.8 

210 

19788.1 

339 

143.3 

5 

u 

73.5 

58.4 

63.9 

5.5 

148.3 

180 

19788.1 

339 

143.3 

6 

Dec. 8. 

74.5 

65.1 

70.2 

5.1 

141.8 

200 

19788.1 

339 

143.3 

7 

a 

72.5 

71.6 

correc. 

69.76 

76.6 

correc. 

4.66 

5.1 

correc. 

142.24 

135.4 

200 

19788.1 

339 

143.3 

8 

a 

73.5 

69.15 

74.4 

5.25 

137.6 

240 

19788.1 

339 

143.3 

9 

a 

72. 

64.8 

correc. 

74.02 

69.9 

correc. 

4.87 

5.1 

correc. 

137.98 

142.1 

210 

19788.1 

339 

143.3 

10 

a 

75. 

70.95 

75.8 

4.85 

136.2 

210 

19788.1 

339 

143.3 

11 

a 

76. 

70. 

75.1 

5.1 

136.9 

240 

19788.1 

339 

143.3 

12 

Dec. 29. 

62. 

61.9 

67. 

5.1 

145. 

240 

20050. 

339 

43.4 

13 

6t 

65. 

—- 

59.8 

64.8 

5. 

147.2 

180 

20050. 

339 

43.4 

14 

1835. 
Jan. 3. 

65. 

60. 

65. 

5. 

147. 

180 

20050. 

339 

43.4 

15 


66. 

59.75 

64.55 

4.8 

147.45 

180 

20050. 

339 

43.4 

16 


66. 

59.6 

64.50 

4.9 

147.5 

180 

20050. 

339 

43.4 

17 


65. 

59.6 

64.40 

4.8 

147.6 

240 

20050. 

339 

43.4 

18 

Jan. 10. 

63. 

65.2 

69.8 

4.6 

142.2 

152 

20050. 

339 

43.4 

19 

a 

62.2 

65.2 

69.8 

4.6 

142.2 

154 

20050. 

339 

43.4 

20 

Jan. 17. 

71. 

66. 

70.7 

4.7 

141.3 

272 

20050. 

339 

43.4 

21 

a 

68. 

63.3 

68.15 

4.85 

143.85 

194 

20050. 

339 

43.4 

22 

a 

61.9 

54.5 

59.8 

5.3 

152.2 

119 

20050, 

339 

43.4 

23 

a 

63.5 

60. 

64.9 

4.9 

147.1 

149 

20050. 

339 

43.4 

24 

Jan. 24. 

63.5 

64.9 

69.5 

4.6 

142.5 

96 

20050. 

339 

43.4 

25 

«( 

71. 

67.1 

71.8 

4.7 

140.2 

145 

20050. 

339 

43.4 

26 

<( 

•71. 

67.1 

71.8 

4.7 

140.2 

153 

20050. 

339 

43.4 


















































25 


T TABLE IV.] capable of containing, in addition to the thermometer and standard piece, 
< about 20,000 grains of water. The iron was heated in a bath of mercury surrounded 
C_by boilinu water , giving it a temperature of 212° at the time of each immersion. 


Weight of 
water and 
equivalent 
of glass and 
thennom. 

Loss of 
temperature 
X weight of 
metal. 

Gain of 
temperature 
X weight of 
water. 

Specific 

heat by the 

uncorrected 

data. 

19656.8 

853200 

104181.04 

.12210 

20270.4 

883200 

107433.12 

.12164 

20270.4 

873000 

107433.12 

.12306 

20270.4 

20270.4 

856800 

889800 

102365.52 

111487.2 

.11947 

.12529 

20270.4 

850800 

103379.04 

.12150 

20270.4 

812400 

101352. 

.12475 

20270.4 

825600 

106420.2 

.12890 

20270.4 

852600 

103379.04 

.12124 

20270.4 

817200 

983114.4 

.12018 

20270.4 

821400 

103579.04 

.12549 

20432.4 

870000 

104205.24 

.11977 

20432.4 

883200 

102162. 

.11567 

20432.4 

882000 

102162. 

.11583 

20432.4 

884700 

98075.52 

.11081 

20432 4 

885000 

100118.76 

.11313 

20432.4 

885600 

98075.52 

.11074 

20423.4 

853200 

93989.04 

.11016 

20423.4 

853200 

93989.04 

.11016 

20432.4 

20432.4 

847800 

863100 

96032.28 

99197.14 

.11327 

.11493 

20432.4 

‘913200 

108291.72 

.11858 

20432.4 

882600 

100118.76 

.11343 

20432.4 

855000 

93989.04 

.10991 

20432.4 

842400 

96032.8 

.11399 

20432.4 

842400 

96032.28 

.11399 


REMARKS. 


1 


fUsing for specific heat of glass, the result 
1 obtained by 10 comparisons, viz. .101911, 


f 


1 


1 


we have the equivalent of the container 
Lin this series=339 grains. 

Began too low. 

C Water gained heat from the air the whole 
\ time of this experiment. 

Final temperature much too low. 

Do. much more so. 

The correction here made is from observ 
ing that ,at the initial temperature 45" 
were required for the air to heat the water 
L.l of a degree. This gives sp. ht.=l 1.068. 
C Exposed to radiation from the stove, gain- 

< ed .1° in 40," when air was 73, water 70.4. 
C Corrected result =.11068. 

(Gained from the air, and from radiation, 

) .05° in 25", or 0.38° in 240", leaving the 

corrected gain 4.87. 

L Corrected result =.11924. 

C Began and ended below the temperature 
of the room; result considerably too high. 
C Ended very near the temperature of the 
\ room ; result too high. 

Ended below the temperature of the room. 

C Began at the temperature of the room— 
\ stove in action. 

Ended below temp, of room ; result too high. 
Mean of 13 preceding results=.123004. 

C Ended at temp, of room. Now shielded the 

< water vessel with a conical tin cover, with 
Can opening to admit the thermometer. 
Shielded as above. 

C Ended below temp, of the external air in 
£room, but the shield was probably lower. 
Do. do. 

C Began 2.2° and ended 6.8° above the 
£ temperature of the air; result too low. 

C Began 3° and ended 7.6° above the air; 
l too low, as before. 

Air in shield probably lower than without. 
Began 4.7 ° below, & ended 8.15° ab. the air. 
C Ended 2.1° below the temp, of the air. 
£ Result consequently much too high. 

C Begun 3.5° below, and ended 1.4° above 
£ the air; a very fair experiment. 

C Began 1.4° and ended 6° above the air; re 
£ suit much too low. 

r Began 3.9° below, and ended 0.8° above 

< the air, received heat a little too long; 
C result, a trifle too high. 

This experiment conformed in conditions 
precisely to the preceding, and the result 
is reproduced. [Mean of last 13=. 11294.] 



















26 


TABLE V. 


Experiments to determine the spcific heat of the iron Standard-piece used in Expe -1 
rimtnts with the Steam Pyrometer employed in this investigation. The heating being > 
performed in a bath of mercury surrounded with boiling water, and the cooling in a j 


No. of Experim’t. 

DATE. 

Temp, of the 
air in the room at 
the beginning 1 . 

Temp, of the air 
at the end of the 
experiment. 

Temp. of air 
inside of shield at 

1 beginning. 

Temperature of 

the air inside at 

the end. 

Evap.point of air. 

| T emperature of 

| the water at the 
| commencement. 

Temperature of 

the water at the 

end. 

Temperature 

gained by the wa¬ 

ter. 

Temperature 

lost by the iron. 

Time elapsed du- 

1 ring the exper’t. 

Weight of water 

used. 


1835. 








o 

O 

// 


1 

Feb. 28, 

58.75 

59. 



48 

52.62 

58.105 

5.495 

153.895 

313 

16728.75 

2 

<< 

57. 

58.25 



48 

56.09 

61.71 

5.62 

150.29 

260 

16728.75 

3 

u 

57.75 

— 



48 

52.33 

57.83 

5.50 

154.17 

319 

16728.75 

4 

(( 

53. 

55,5 



48 

49.35 

55.28 

5.93 

156.72 

135 

16728.75 

5 

A pi. 7, 

67.1 

68.5 



49 

63.50 

68.94 

5.44 

143.06 

177 

16494.5 

6 


67.1 

67.7 



49 

63.52 

68.97 

5.45 

143.03 

unc 

16494.5 

7 

u 

67.15 

66.70 



50 

63.50 

68.90 

5.4 

143.1 

unc 

16494.5 

8 

(( 

67.1 

67.58 



50 

63.50 

68.90 

5.4 

143.1 


16494.5 

9 

Apl. 18, 

58, 

58. 

55. 

55.25 

51 

53.3 

59.09 

5.79 

152.91 


16494.5 

10 

(< 

60. 

60.5 

56. 

56.5 

51 

52.46 

58.34 

5.88 

153.66 


16494.5 

11 

a 

62. 

62. 

58.25 

58.5 

51 

51.3 

57.28 

5.98 

154.72 


16494.5 

12 

M 

57. 

57. 

53.5 

53.5 

51 

46.7 

52.92 

6.22 

159.28 


16494.5 

13 

Mar. 28, 

66 . 

66 . 

64. 

64.4 


60. 

65.49 

5.49 

149.51 


16494.5 

14 

<< 

|66. 

66 . 

65.2 

65.2 


60. 

65.51 

5.51 

146.49 


16494.5 






































27 


TABLE V. 

'glass cylindrical jar, weighing 12272 grains, and receiving such a quantity of water at 
each experiment as completely to Jill the jar when the thermometer and the iron wer$ 
immersed. Weight of dtandard-piece 6000 grains. Temperature at immersion 212°. 


Liquid in therm, 
in grs. ofits equi¬ 
valent of water. 

Total weight of 

glass m grains in¬ 
cluding that of 
the therm, bulb. 

Equivalent of 

glass in grains of 

water. 

Total equiva¬ 
lent of water 
heated. 

Weight of iron 
X its loss of 
temperature. 

Weight of total 

equivalent of wa¬ 

ter X its gain of 
temperature. 

Specific heat of 

iron. 

91 

12536 

1391.5 

18210. 

923370 

99881.85 

.10817 

91 

12536 

1391.5 

18210. 

901740 

102340.2 

.11348 

91 

12536 

1391.5 

18210. 

925020 

100155. 

.10827 

91 

12536 

1391.5 

18210. 

940320 

107985.3 

.11482 

152.7 

12706 

1275.2 

17922.4 

858360 

97497.856 

.11358 

152.7 

12706 

1275.2 

17922.4 

858380 

97677.08 

.11382 

152.7 

12706 

1275.2 

17922.4 

858680 

96780.96 

.11272 

152.7 

12706 

1275.2 

17922.4 

858600 

96780.96 

.11272. 

152.7 

12706 

1275.2 

17922.4 

917460 

103770.696 

.11310 

152.7 

12706 

1275.2 

17922.4 

921960 

105383.712 

.11430 

152.7 

12706 

1275.2 

17922.4 

928320 

107175.952 

C.11545 

C_ too high 

152.7 

12706 

1275.2 

17922.4 

955680 

111477.328 

C. 11560 

C. too high 

152.7 

12706 

1275.2 

17922.4 

379060 

98393.976 

.11193 

152.7 

12706 

1275.2 

17922.4 

378940 

98952.424 

.11235 


REMARKS. 


Mean of 14=. 11288 
Mean of Nos. 2, 5, 6 and 9=. 11349 


This and the three fol¬ 
lowing’ experiments were 
made with the water begin 
ning at temperatures cor- 
j responding to those of a s e- 
t ries of the same number, 
made in a thin glass vessel 
having precisely the same 
capacity as the one now 
v_used. 

The thermometer here 
used is the long-bulb spirit 
instrument C, the specific 
heat of which is only ap¬ 
proximately estimated, the 
glass at 264 grains, and the 
alcohol atj242. 

This experiment began 
and ended below the tern 
perature of the air. The 
result is consequently too 
high. 

This and the three fol¬ 
lowing were made by the 
aid of thermometer A, hav¬ 
ing a bulb 7 1-2 inches 
long,containing at 62 t> 4670 
grains of mercury. 

These th ree experiments 
| were intended to coincide 
I with two others made in a 
Vseries with the thin glass 
I j ar; the mean of these three 
is .11312, that of the other 


The four following co 
incide nearly with three 
others made in a series with 
the thin glass of the same 
capacity. These several 
comparative portions of 
the two series were made 
with a view of obtaining 
from them the specific heat 
of glass. Weight of glass 
bulb of thermometer A, 
was carefully ascertained 
after it had been broken,& 
found to be 433.85 grains. 
To avoid fractions, it is 
here taken at 434. The 
weight of mercury de¬ 
termined by weighing at 
the time of filling the in¬ 
strument. 

This and the following - 
may furnish a comparison 
with the 10th experiment 
in the table of those made 
in the thin cylinder of the 
same capacity. By that 
comparison the specific 
heat of glass appealed to 
be .10036. 

These four are the great¬ 
est number which conform 
as far as to the third place. 


3 





































28 


TABLE VI. 

TABLE VI .—Experiments to determine the specific heat of the iron standard piece 
used in experiments with the steam pyrometer, employed in this investigation. The 
heating being performed in a bath of mercury, surrounded with boiling water, and 
cylindrical jar, weighing 2996 grains, receiving such quantities of water, at each ex- 


No. of experi.j 

DATE. 

Temp, of air 

at beginning 1 . 

Temp, of air 

at the end. 

Temp, within 
the tin cylin¬ 
der at the be¬ 
ginning. 

Temperature 
in the cylinder 

at the end. 

|Evapo. point. 

Temperature 

of the water at 

beginning. 

Temperature 

of the water at 

the end. 

Temperature 

gained by the 

water. 

Temperature 

lostbytheiron. 

Time elap. du¬ 

ring the exp. 

Weight of wa¬ 

ter used. 










1' 

t' 


W. 

1 

1835. 
Feb. 21, 

o 

57.5 

o 

58. 

o 

O 

o 

50 

O 

56.09 

o 

61.95 

o 

5.86 

o 

150.35 

185" 

ers. 

16728. 

2 

tt 

58.5 

59, 



51 

52.62 

58.70 

6.08 

153.3 

325 

16728. 

3 

a 

57. 

57.5 



47 

52.33 

58.11 

5.78 

153.89 

309 

16728. 

4 

a 

56.5 

56.5 



47 

49.35 

55.66 

6.31 

156.34 

464 

16728. 

5 

April 7, 

57.2 

67.5 



49 

63.51 

69.22 

5.71 

142.78 

154 

16494.5 

6 

<( 

67.1 

68.2 



49 

63.50 

69.26 

5.76 

142.74 

157 

16494.5 

7 

1 

April 18, 

60. 

60. 

56.75 

57.25 

52 

53.43 

59.58 

6.15 

152.42 


16494.5 

8 

u 

60. 

59. 

57.75 

57.5 

53 

52.46 

58.64 

6.18 

153.36 


16494.5 

9 

u 

62.5 

63. 

59.25 

59.2 

53 

51.44 

57.76 

6.32 

154.24 


16494.5 

1C 

Marh. 28. 

65. 

65. 

63. 

63.6 


60. 

65.79 

5.79 

146.21 


16494.5 
























































29 


TABLE VI. 

per intent, as completely to Jill the jar when the thermometer and the iron were immersed. 
J Weight of the standard piece , 6000 grains,—temperature at immersion , 212.° 
j Weight of glass container and of thermometer bulb 3250 grains. 


Equivalent of 
liquid in the 
ther. in grains 
of water. 

Equivalent of 
glass in grains 
of water. 

Total equiva¬ 
lent of water 
heated. 

8 ® • 

U V 

Cfl ^ 

c W 2 3 

° " 2 

§.S t 
£ s 

Weight of e- 
quivalents of 

water X its 

gain of tempe¬ 

rature. 

Specific heat 

of iron. 

e. 

grs. 

91. 

360.7 

grs. 

17179.7 

90210 

100674.8 

.11160 

1 

91. 

360.7 

17179.7 

919800 

104454.4 

.11356 

91. 

360.7 

17179.7 

923340 

99300.4 

.10754 

91. 

360.7 

17179.7 

938040 

108405.8 

.11556 

132.7 

300.6 

16947.8 

856680 

96771.938 

.11296 

152.7 

300.6 

16947.8 

856440 

97619.328 

.11398 

152.7 

300.6 

16947.8 

914520 

104228.91 

.11397 

152.7 

300.6 

16947.8 

920160 

104737.404 

.11405 

152.7 

300.6 

16947.8 

915440 

107110.095 

.11574 

152.5 

300.6 

16947.8 

877260 

98127.762 

.11185 


REMARKS. 


The first four experiments were 
performed with a thermometer of 
spirits of wine, the degrees of 
which were divided into lOOths, 
but the performance of instru¬ 
ments of this sort being liable to 
inaccuracy from the different 
quantities of liquid taken up at 
different times in wetting the in¬ 
terior of the tube, the confidence 
reposed in these results is less 
than in those of the series with 
the mercurial therm. (A). The 
3d exp. of this table with the 3d 
of the preceding table gives for 
specific heat of glass .09651. 

As the whole process was per¬ 
formed below the temperature of 
the air, this result must obvious¬ 
ly be too high, compared with 
exp. 4 of preceding table, this 
gives spec, heat of glass. 12317. 

This experiment compared 
with experiments 7 and 8 of the 
preceding series give for specific 
heat of glass .110202. 

This experiment compared 
with No. 6 of preceding table, 
gives for specific heat of glass, 
.11100, but compared with Nos. 
7 and 8 it gives .130156. 

Compared with experiment 9 
of the preceding table, this trial 
gives for an approximate specific 
heat of glass, .12662. 

With experiment 10 of pre¬ 
ceding table this gives .09715 for 
specific heat of glass. 

This experiment was both be¬ 
gun and ended below the tempe¬ 
rature of the air. The result 
must consequently be too high. 
Compared with experiment 11 
preceding table, it gives specific 
heat of glass .110404. 

Specific heat of glass derived 
from a comparison of this experi¬ 
ment with Nos. 13 and 14 of the 
series in the thick jar is .10036. 

Mean sp. ht. of glass .111063. 





























TABLE VII. 


Experiments to determine the specific heat of the iron standard piece used in experi-^\ 
ments with the steam pyrometer employed in this investigation. The heating being l 
performed in a bath of mercury surrounded with boiling water, and the cooling in two { 
different glass vessels in the two divisions of the series , the heavier weighing 6923,J 


DATE. 


1835. 
Mar. 16. 


a 

'5 . to 

a <l» .2 
o'd C 

J.s 

s 

4) 4) 


44 




April 4. 


<< 


it 


65 


64.8 

65.7 

67. 

67. 

65.75 


8 


Mar. 16. 


4 4 


10 

1 

2 


<( 


April 4. 


<< 


(< 


65.6 


65.5 

65.3 

66.25 

66 . 

66.5 


es 

u w 
a rt 
O, 

j= a 

Eh^ . 

w C/1 _j 

= a 
o a 


65.5 


65. 

65.8 

68 . 

66 . 

66.25 


65.9 


65.8 

65.4 
66.25 

66.1 

66.5 


O 03 
a . & 

•a a 
5 13 5 
s a c 
"r^-So 

a, S’ a 

£ ^ 
a fl « 

” ^ W 


0) 

rs 

*«« 

c 

p/fi 

g " 
8 2 
r 1 *3 


65.2 

65. 

65. 


66.1 

65.2 

65.9 


65.7 

65.3 

65.3 


66.3 


65.5 


66.1 




a 


a « to 


s-« .2 
* *£jD 


60.5 


60.5 

60.5 

60. 

60.02 

60.01 


60.5 


60.5 

60.5 

60. 

60. 

60. 


°a 

V <U 


cs 

<V c3 

£2 
a a 
r 1 ? 


68.66 


68.74 

68.72 

68.36 

68.27 

68.38 


68.88 


69. 

69. 

68.56 

68.68 

68.68 


i*-* 

as 

Pi 

i $ 

tt 

o 

c £ 
'3 

©•5 


T 

o 


8.16 


8.24 

8.22 

8.36 

8.25 

8.37 


CZ G 

fe 2 

or'’ 

£ 2 
QJ — 

*-» ♦-* 

0.0 

I a 

>-) 2 


t 

o 


143.34 


143.26 

143.28 

143.64 

143.73 

143.62 


8.38 


8.50 

8.50 

8.56 

8.68 

8.68 


V 

143.12 


143. 

143. 
143.44 

143.32 

143.32 


1= . 

.2 a 

s * 

Q OJ 

PS 

*■* 

^ & 


// 


137" 

141 

125 


170 


0> 

■*j • 

c3 «« 
£.2 

r. . c3 

° So 

•4J 

.Sft£ 

C/i 

? 3 


w 


10872 


10872 

10872 

10800 

10800 

10800 


w 
10872 


10872 

10872 

10800 

10800 

10800 


a c c 

2 = 5 

a 2 5) 

<« a 

© a-~ u 
• a 
> ^ 

3 a a g 

w 


152.7 


152.7 

152.7 

152.7 

152.7 

152.7 


e 

152.7 


152.7 

152.7 

152.7 

152.7 

152.7 




























































31 

TABLE VII. 


'and the lighter 2465 grains, receiving equal quantities of water, so as accurately to 
fill them when the standard piece and the thermometer were immersed. Weight of 
tlte standard-piece 6000 grains ; its temperature at immersion, 212°. 


to bf) .* 

C f) Z? U 

03 C GJ . 

*2c 

i 

*-> 

a 

p i 

co * 

• - 2 

Cm 

o 


Wright of gl 
in the containi 
vessel ami th 
mometer bulb 

Equivalent 
the containi 
vessel in wate 

Amount of m 
ter heated. 

Weight of ii 
X loss of tem] 
rature. 

Water X 

gain of tempe 

ture. 

1 

Specific heat 

iron. 

remarks. 

s 






Thicker glass jar. 

grs. 

grs. 




The first three of these ex- 





periments were made under 
the tin cone, the next three 



7356 

=4334-6923 

740.16 

11764.8 

860040 

96001.584 

.111624 

within the tin cylinder with 
the cover affixed. The cone 
could not altogether prevent 
the circulation of air around 







the containing vessel. 







The mean result of 2d and 
3d experiments may be com- 

7356 

740.16 

11764.8 

859560 

96941.952 

.112780 

pared with the identical re¬ 
sults of the 8th and 9th, and 







the formula for that compari- 







son is 

7356 

740.16 

11764.8 

859680 

96706.656 

.112244 


Tt'g—T'tg' h P 

cific heat of glass of this de¬ 
scription. 







7356 

740.16 

11692.9 

861780 

97811.004 

.113498 

The mean result of the 4th 




.111860 

and 6th experiments may in 
like manner be compared 



7356 

740.16 

11692.9 

862380 

96466.425 

with the identical results of 
the 11th and 12th. 


7356 

740.16 

11692.9 

861780 

97811.004 

.113498 


2898 






Thinner glass jar. 

290.59 

11315.3 

858720 

94822.214 

.110422 

The 7th, 8th and 9th expe¬ 
riments were made under the 
tin cone, and the 10th, 11th 
and 12th within the tin cylin- 

24654-=433 







der, the error of one-tenth of 
a degree is suspected to have 







occurred in the reading of the 
7th experiment. 

The equivalent for the con¬ 
taining vessel in this and the 

2898 

290.50 

11315.3 

858000 

96180.05 

.112098 

following experiment as de¬ 
rived from a comparison with 
the 2d and 3d experiments of 
this series, is 1254. 85,and this 
gives sp. lit. of iron .111743. 

2898 

290.59 

11315.3 

858000 

96180.05 

.112098 


2898 

290.59 

11315.3 

860640 

96242.648 

.111816 

The equivalent for the con- 

2898 

290.59 

11243.3 

859920 

97591.844 

.113489 

tainer for this and the follow¬ 
ing experiment is derived by 

2898 

290.59 

11243.3 

859920 

97591.844 

.113489 

formula, from a comparison 
with experiments 4 and 6, by 



which the specific heat oi 






.112409 

glass appears to be. 100620. 







Comparing for the specific 
heat of glass we get from ex¬ 
periments 







1 and 8 - .115040 

4 and 11- .100082 

5 and 10- .100004 

6 and 11- .098884 







4 with 11 and 12- .100620 







Mean .103086 


3 * 


































32 


TABLE VIII. 


Experiments to determine the specific heat of the Iron Standard-piece used in expc- 
riments with the Steam Pyrometer employed in this investigation , the heating being L 
performed in a bath of mercury surrounded with boiling water, the cooling in twoj 


Number of the 
Experiments. 

DATE. 

Temperature 
of the air outside 
of the tin cy¬ 
linder at begin¬ 
ning. 

Temp, outside 
of the tin cylind. 
at the end. 

Temperature 
within the cy¬ 

linder at begin¬ 
ning. 

Temperaturt 

within at the 

end of the expe¬ 

riment. 

Temperature 

of the water at 

the commence¬ 

ment of the ex¬ 
periment. 

Temperature 

of water at the 

end. 

Gain of tem¬ 

perature by the 
water. 

Loss of tempe¬ 

rature by the 
iron. 

1 

1835. 
May 2, 

O 

66 . 

o 

66.5 

o 

65.2 

o 

62.7 

o 

49.62 

o 

52.60 

0 

2.98 

o 

159.40 

2 

a 

66.25 

67. 

64.5 

63. 

53.70 

56.54 

2.84 

155.46 

3 

a 

66 . 

66.25 

63.5 

63.2 

57.06 

59.82 

2.76 

152.18 

4 

< i 

66 . 

66.5 

63.8 

64.1 

60.22 

62.84 

2.62 

149.16 

5 

a 

66 . 

66.25 

64.8 

65.15 

62.95 

65.42 

2.47 

146.58 

6 

a 

66 . 

66 . 

65.6 

65.8 

63.28 

65.75 

2.47 

146.25 

7 

it 

66.5 

67. 

66.2 

66.6 

65.78 

68.31 

2.53 

143.69 

8 

1835. 
May 9, 

67. 

67. 

66.9 

66.9 

63.88 

66.34 

2.46 

145.66 

9 

u 

66.5 

67. 

67.1 

67.1 

65.78 

68.26 

2.48 

143.74 

10 

May 16, 

64. 

64. 

62.2 

61.4 

51.80 

54.54 

2.74 

157.46 

11 

a 

64. 

64. 

61.4 

61.2 

55.00 

57.67 

2.67 

154.33 

12 

a 

64.25 

64.5 

61.9 

62.1 

58.09 

60.72 

2.63 

151.28 

13 

a 

65. 

65. 

62.8 

63. 

60.88 

63,31 

2.43 

148.69 

14 

a 

65, 

65. 

63.8 

64.2 

43.42 

65.81 

2.39 

146.19 

15 

a 

65. 

65. 

64.6 

65.25 

65.81 

68.26 

2.45 

143.74 

16 

a 

65, 

65. 

66 . 

66.5 

68.20 

70.64 

2.44 

141.36 

17 

a 

65. 

65. 

67. 

67.2 

70.46 

72.72 

2.26 

139.28 

18 

a 

65. 

65. 

66.5 

66 . 

63.28 

65.66 

2.38 

146.34 



















































33 


TABLE VIII. 


‘ different copper vessels capable of receiving equal weights of water , but having dif¬ 
ferent thicknesses. Weight of the Standard-piece at the time , 6000 grains , and its 
temperature at immersion 212°. 


Weight of wa¬ 
ter employed. 

Equivalent of 

the thermometer 
in grains of wa¬ 
ter. 

Weight of the 
copper cylinder. 

Equivalent of 

the containing 
vessel in grains 
of water. 

Total matter 
heated. 

Specific heat. 

REMARKS. 

g-rs. 

grs. 

grs. 

grs. 

grs. 



38659 

196 

5178 

540 

39395 

.122169 

The first three experiments 
were begun and ended so far 

38659 

196 

5178 

540 

39395 

.119380 

below the temperature of the 
air, that the water must ob- 

38659 

196 

5178 

540 

39395 

.118504 

viously have received heat from 
the latter during the whole time. 

38659 

196 

5178 

540 

39395 

.114784 

38659 

196 

5178 

540 

39395 

.110100 


38659 

196 

5178 

540 

39395 

.110366 

Mean of the whole 7 experi¬ 
ments.=11595. 

38659 

196 

5178 

540 

39395 

.115061 

Mean of the last 4.=11257. 

38659 

196 

19738 

2056.8 

40911.8 

.114411 

This and the last six are con¬ 
sidered comparable. 

38659 

196 

19738 

2056.8 

40911.8 

.118052 

This and the three following 
give results varying from the 

38659 

196 

19738 

2056.8 

40911.8 

.118676 

rest, partly on account of an ex¬ 
cess of heat which kept the 

38659 

196 

19738 

2056.8 

40911.8 

.117933 

steam in the heating apparatus a 
little too high. 

38659 

196 

19738 

2056.8 

40911.8 

.117407 

38659 

196 

19738 

2056.8 

40911.8 

.111405 


38659 

196 

19738 

2056.8 

40911.8 

.111318 


38659 

196 

19738 

2056.8 

40911.8 

.114565 


38669 

196 

19738 

2056.8 

40911.8 

.117661 


38659 

196 

19738 

2056.8 

40911.8 

.110609 


38659 

196 

19738 

Mean 

Mea 

2056.8 

of all fr 

n of 7 c 

40911.8 

om 8 to 18 

omparable 

.110869 

=.114990 

=.113261 

This experiment with No. 6, 
gives by calculation the specific 
heat of copper .10431. 





































TABLE IX. 


Experiments to determine the specific heat of the Iron Standard-piece used in experiments -with the Steam ? 
Pyrometer. The heating being performed in the bath of mercury surrounded :with boiling water, and the 3 


z 

X 

w 

o 

o 

£ 

DATE. 

Temp, of air out¬ 
side enclosure at 
beginning of exp. 

Temp, of air out¬ 

side at the close of 
the experiment. 

Temperature of 

air inside of the 

enclosing cylin¬ 

der at the begin- 
1 ning. 

Temperature of 

air inside at the 

end. 

g 

O 

PH 

JbJD 

o3 

3 

c? 

> 

w 

Temp, of water 

at the moment the 

iron was immers’d 

Temperature of 

the water at end 

of the operation. 

Temperature 

gained by the 

water. 

Temperature 

lost by the iron. 

Time elapsed du¬ 

ring experiment. 

Weight of water 

in grams Troy. 


'1835. 

O 

o 



« 

o 

O 

o 


u 


1 

Feb. 7, 

05.5 

66.5 

> 



50 

60.8 

68.1 

7.3 

143.9 

91 

13022 

2 

u 

68.25 

69.5 



50 

59.9 

67.3 

7.4 

144.7 

109 

13022 

3 

Mar. 21, 

66 . 

66 . 

C 62.° 

62° 1 


51.74 

59.87 

8.13 

152.13 

376 

12480 





59.5 

59.9 5 








4 

it 

66 . 

66 , 

C 64. 

64. 1 


59.4 

67.11 

7.71 

144.89 


12480 





62.9 

63.55 3 








5 

a 

67. 

66.5 

C 64.5 

64. ) 


57.15 

64.96 

7.81 

147.04 


12480 





£ 68.45 

68.3 3 








6 

Mar. 28, 

63.8 

64. 

63.7 

63.9 


60, 

67.79 

7.79 

144.21 

157 

12480 

7 

a 

65. 

65, 

64. 

64.5 


60, 

67.78 

7.78 

144.22 


12480 

8 

Apl. 25. 

62,5 

63. 

60.5 

60.5 


54.51 

62.52 

8.02 

149.48 


12240 

9 

d 

62.5 

62.5 

62, 

63. 


62.50 

69.86 

7.36 

142.14 


12240 

10 

u 

63. 

63.5 

63.1 

63.1 


56.3 

64.06 

7.76 

147.94 


12240 

11 

a 

63. 

63.5 

61.8 

62. 


56.3 

63.90 

7.60 

148.1 


12480 

12 

u 

64. 

64. 

62. 

62.2 


56.3 

63.91 

7.61 

148.09 


12480 








■s- 






13 

u 

63.5 

64. 

61.9 

62.2 


56.3 

64.10 

7.80 

147.9 


12480 

14 

u 

63. 

63. 

61.8 

63.5 


56.3 

64.09 

7.79 

147.91 


12480 




































35 


TABLE IX. 

C cooling in sheet-iron cylinders of different thicknesses. The standard-piece atthc time weighed 6000 grains 


Weight of the 
iron containing 
vessel. 

Equivalent of 

the thermometer 
in grs. of water. 

Sum of the weight 
of water and ther¬ 
mometer equiva¬ 
lent. 

Weight of water 

X its gain of tem¬ 
perature. 

Weight of iron 

X its loss of tem¬ 

perature. 

Weight of con¬ 

tainer X its gain 
of temperature. 

Specific heat 

by formula. 

T (w -+- e) 

- v 

< 

so 

H 

1 

1733 

43.4 

13065.4 

95377.42 

863400 

12534.1 

.112220 

1733 

43.4 

13065.4 

96683.9 

868200 

12705.8 

.113010 

1733 

196. 

12676. 

103055.8 

912780 

13959.21 

.114655 

1733 

196. 

12676. 

97731.96 

869340 

13238.07 

.114159 

1733 

196. 

12676. 

98999.56 

882240 

13409.77 

.113945 

1733 

196. 

12676. 

98746.04 

865260 

13375.43 

.115914 

1733 

196. 

12676. 

98609.08 

865320 

13358.26 

.115743 

5167 

196. 

12436. 

99736.72 

896880 

41439.34 

.116581 

5167 

196. 

12436. 

91529. 

852840 

38029.12 

.112321 

5167 

196. 

12436. 

96495.6 

887640 

40095.92 

.113735 

5167 

196. 

12676. 

96339. 

888600 

39269.2 

.113418 

5167 

196. 

12676. 

96456.75 

888540 

39320.87 

.113713 

1733 

196. 

12676. 

98875.8 

887400 

13517.6 

.113142 

1733 

196. 

12676. 

98738.25 

887460 

13500.07| 

.112962 


REMARKS. 


Mean of 14=. 113963 


{ In this and the two fol¬ 
lowing trials the container 
was exposed to the direct 
action of the air, and to 
radiation from the stove. 

Near the conclusion of 
this experiment the ther- 
mometer in the water rose 
i rapidly, and soon after fell 
“X several tenths, indicating 
I the existence of currents of 
j unequally heated portions 
'-of water. 

The container was now 
placed on a charcoal stand 
within a tinned iron cylin¬ 
der, 9 inches in diameter, 
i 14 inches high, through the 
\ side of which, near the hot' 
tom, passed the stem of a 
thermometer, another be 
ing within it near the 
top, the scale projecting 
^-above. 

In this experiment, ther¬ 
mometers in the air were 
all observed to have fall¬ 
en during the operation. 

f~ A tin cover perforated 
| at top to receive thermo- 
J meters, and the iron to be 
j tried, was now placed over 
1 the tin cylinder. 
r Only one thermometer 
J now pi aced in the inside of 
"X the tin vessel,its bulb at the 
I level of the middle of the 
Lwater cylinder. 

f This experiment ended at 
I the temperature of the air, 
J and may be supposed to 
give a result too high ; a lit- 
| tie pressure of steam in the 
I boiler. 

r~ This experiment having 
l been begun at tbe tempera- 
| ture of the air may be sup 
posed to give a result too 
low, the inner air-thermo¬ 
meter rose above the exte¬ 
rior air. 

r- Half an ounce more water 
j used in this than in the 
3 preceding experiments. 
I Care was taken to regulate 
<( the height of the furnace so 
as to keep the temperature 
precisely at the boiling 
point, and not to increase 
^-the pressure. 

"* These two experiments in 
the thinner cylinder were 
intended to furnish a 
means of comparing the 
J 2 vessels with each other, 
t The result shows the speci¬ 
fic heat of sheet iron = 
.101714. With this specific 
heat,the mean result of the 
■last four trials is .112945. 









































36 


After the preliminary series already given, (Tab. IV.) two other sets of 
experiments were made, one in each of two glass vessels similar to that 
in which the preceeding trials had taken place,—equal to each other in 
liquid capacity, but of different thicknesses; the one being more than four 
times as heavy as the other. Table V. contains the experiments with the 
thicker, and table VI., those with the thinner of these vessels. The 
particular object of these trials was to determine, if possible, the effect of 
the containing vessel on the general result of the experiment; in other 
words, to decide its specific heat, by observing the difference which would 
arise from a mere change of thickness in the containing vessel, while all 
other circumstances of the trial were the same, in both cases. A comparison 
of several experiments in each table, with corresponding ones in the other, 
will show that when the water at the commencement was from 60° to 
63.5°, the actual difference in the rise of temperature, due to a difference 
in the weight of the containing vessels of (12272—2996)=9276 grains of 
glass, was about three tenths of a degree ; and from the comparison of nine 
experiments in the first of these tables, with the same number in the second, 
it will be seen that we obtain for the specific heat of glass .111063.* A part 
of the trials in these and the subsequent series were made by means of the 
spirit thermometer C, the equivalent of which was only approximately found, 
on account of not having taken the precaution to weigh the bulb and tube 
separately before filling the instrument. It is, also, like all other spirit 
thermometers, liable to some uncertainty in its indications owing to the 
different quantities of the liquid which may at different times be taken up 
in wetting the tube,—an uncertainty, which is the greater, the more sudden 
are the changes to which we submit the instrument. 

The equivalent value assigned to it by finding the weight and capacity 
of an equal length of the same tube is 117.4 grains of water, as hereafter 
mentioned. 

The next apparatus used in this part of the investigation consisted of two 
glass jars, smaller than those above described, both of the same capacity, 
but differing from each other in weight, being nearly in the proportion of 
3 to 1. The experiments in these two vessels were made in two sets of 6 
each, three of each set being commenced in the thicker vessels at a 
temperature of 60°, and three at 60.5°; and the same number at the same 
two points in the thinner. The results are contained in table VII., where 
it will be perceived that from five comparisons between the trials in these 
two jars the influence of the glass is such as to indicate a mean specific 
heat of .103086, which taken with the above result of the 9 comparisons 


* The principle of calculation applied to all these comparisons is embraced in 
the formula x = i JL f ~ J . / _ )'^ ) ’ where x is the specific heat of the container ; 


T' is the gain of temperature by the water when the thinner glass is used ; T the 
gain when the thicker vessel is employed ; is the loss of temperature by the iron 
when the thinner, and t, that when the thicker is employed; w , is the weight of 
water in both cases, and e the equivalent in grains of water, of the liquid in the 
thermometer; g is the weight of the thicker jar; g' that of the thinner. Thus compar¬ 
ing the two identical experiments 7 and 8, table V., with experiment 6, table VI. in 
which the initial temperature of the water, and other circumstances, coincided 
with the formei, we have T r — 5°.76; £=143°.l; T=5°.4; t'= 142°.74 ; w — 
16494.5 grs.; e = 152.7 grs.; g = 12. 706 grs., and ^ = 34.30 grs. Hence T't 
= 824.256; Tt'= 770.796; T't—Tt' = 54.46 ; w+c = 16.647.2 ; Tt'g = 
9793733.976; T'tg' = 2827198.08 ; from which x = .130156 the specific heat of 
the glass by this comparison. 



37 


between tables V. and VI., gives a mean specific heat of flint glass of 
.107074. 

As we are now only referring to the apparatus employed, we shall 
reserve our remarks on the results presented by these tables, respecting the 
specific heat of iron , until we have described the other methods of verifying 
their correctness. 

The fourth set of apparatus for this purpose, consisted of two cylindrical 
copper vessels, of the same height as the glass ones already described : but 
of such diameter as to contain about 38600 grains, or a little over5£ pounds 
avoirdupoise of water, and so differing in thickness, that the one weighed 
nearly 4 times as much as the other. The mode of conducting experiments 
in these two vessels, and the principle of calculation applicable to them, is 
entirely similar to that already given for the two pairs of glass jars,— 
except that the equivalent of the glass in the thermometer, was now sepa¬ 
rately computed. 

The results will be found in table VIII., in which it will be perceived 
that the number of comparisons furnishing data for determining the specific 
heat of copper, is but two, and of these only one can be considered entirely 
unexceptionable. 

From this it should seem that the specific heat of copper is .10431, 
whereas the four determinations of Wilke, Crawford, Dalton and Petit and 
Dulong give .10750 for the specific heat of that metal. 

A fifth mode of determining the specific heat of iron was by employing 
as water vessels two cylindrical sheet iron jars of the same capacity, but of 
thicknesses differing from each other in about the proportion of 3 to 1. As 
in the preceding sets, the specific heat of the container may here be found 
by comparing together experiments made at the same temperature, in the 
two vessels; and this ought to give their variation, if any exist, from the 
specific heat of the standard piece itself. Another method is to assume that 
the specific heat of the standard piece and of the sheet iron containers is the 
same.* The use of the two containers in this latter case serves only to 
verify each others results, since each furnishes a separate and independent 
calculation. 

The results of experiments in the two iron vessels will be found in table 
IX. A comparison furnished by two experiments in each vessel, gives by 
calculation on the principle used in the case of the glass containers the spe¬ 
cific heat of the Russian sheet iron, of which they are composed = .101714. 

Results of Experiments on Specific Heats. 

When it is considered that numerous causes interfere with the operations 
on specific heats, it cannot be expected that one, or a few trials, should be 
deemed sufficient to settle so difficult and intricate a question. For this 
reason the committee preferred the method of multiplying and varying the 
trials, and making a deduction from the mean results, in order to verify the 
general efficacy of the standard piece, in producing vapour. 

1. The first part of the preliminary series (table IV.) indicates the 
effect of radiation from surrounding objects in the apartment to the water 


# 


The formula in this case gives the specific heat of iron z — 


T(w + e) 
it — i' T 


where T 


is the temperature gained by the water, w = the weght of water in grains, e = the 
equivalent of the thermometer in grains of water; t — the temperature lost by the 
standard piece; t = the weight of the standard piece in grains, and i' = the weight 
of the sheet iron containg vessel. See Am. Jour, of Sci. Vol. 27, p. 277. 



38 


vessel. The 13 experiments constituting this part of the table, exhibit a 
mean result of .123004 as the specific heat of iron. 

2. The second part of the same series in which the cylinder B. was 
employed, indicates a decided effect from that precaution, and gives as a 
mean result .11294, for the specific heat. 

3. Experiments No. 16, 20, 23, 25 and 26, the greatest number of com¬ 
parable results in this part of the series, (differing only in the fourth place of 
decimals,) gives a mean of .11346. 

4. In table V., where the thicker of the two glass cylinders of the same 
capacity was used, we have the mean result of the whole 14 experiments 
.11288. 

5. The four experiments No. 2, 5, 6, and 9, which are the greatest 
number that conform to the third place, give a mean result of .11349. 

6. The 10 experiments in table VI., made in the thin cylinder of the 
same capacity as the foregoing, give the specific heat = .11308. 

7. Experiments No. 2, 5, 6 and 7, the greatest number of those which 
may be regarded as conformable to the third place of decimals, give a mean 
of .11361. 

8. Table VII. contains 3 experiments made in each of the two vessels 
used in that series, which were performed under a cone of tinned iron to 
defend the water vessel from radiated heat, but as it was set loosely on the 
table which supported the container, it did not prevent the motion of air 
around the latter, and as the experiments made in this manner terminated 
from three to four degrees above the temperature of s the room, there is 
reason to suppose that the results of those 6 experiments are all below the 
truth. Taking then the other six of this table, which were made w r ith the 
same precautions as those in table V. and VI., we have as the mean result 
in the thicker glass .112952 ; and that in the thinner .113631. 

9. The two experiments which confoim entirely with each other, for the 
thicker vessel, give the specific heat .113498, and the two for the thinner 
.113489. 

10. The mean of all the results, including both those obtained with the 
cone, and those with the cylinder of tinned iron, to defend the water vessel, 
give a mean result of .112350, and the six rejected experiments taken by 
themselves .111511. 

11. In the thinner copper vessel, the trials as recorded in table VIII, ex¬ 
hibit the mean of seven results equal to .115752 

12. Rejecting those which began and ended too low, and hence gained 
heat from the air, as well as from the iron, we have in the thinner vessel 
.112577 as the mean of four experiments which are considered comparable. 

13. In the same table eleven experiments in the thicker vessel indicate a 
a mean of .114990. 

14. With the same jar, seven experiments which are considered com¬ 
parable, give a result equal to .113261. 

15. In the thick sheet iron cylinder, weighing 5167 grains, we find by 
table IX., that the mean of five trials gave a result = .113953. 

16. In the same vessel, three experiments which differ only in the 
4th place of decimals give a mean specific heat =.113622. 

17. In the thinner sheet iron jar weighing 1733 grains, nine trials gave 
a mean result of .112972. 

18. Three experiments in this vessel which differ only in the fourth 
place of decimals, give a mean of .113365. 

The following table embraces a synoptical view of the experiments on 
specific heat thus far detailed. 


39 


TABLE X. 


No. of the comparison. 

No. of the table referred to. 

Kind of containing vessel 
used. 

Weight of the vessel in grs. 

No. of experiments compar¬ 

ed for the general mean. 

Mean of specific heats from 

a comparison of all the trials. 

No. of comparable experi¬ 

ments differing in the fourth 
place of decimals. 

Mean specific heat by the 

comparable results. 

No. of rejected experiments. 

Mean specific heat by the 

rejected experiments. 

1 

IV. 

Thin glass. 

3325. 

13 

.112940 

5 

.113460 

13 

.123004 

2 

V. 

Thick glass. 

12272. 

14 

.112880 

4 

.113490 





Thin, containing 








3 

VI. 

same as preceding. 

2996. 

10 

.113080 

4 

.113610 



4 

VII. 

Thick small glass. 

6923. 

O 

o 

.112952 

2 

.113498 

6 

.111511 

5 

VII. 

Thin small glass. 

2465. 

3 

.112931 

2 

.113489 



6 

VIII. 

Thick copper. 

19738. 

11 

.114990 

7 

.113261 



7 

VIII. 

Thin copper. 

5178. 

7 

.115752 

4 

.112577 



8 

IX. 

Thick iron. 

5167. 

5 

.113953 

3 

.113622 



9 

IX. 

Thin iron. 

1733. 

9 

.113972 

3 

.113365 







75 

.113716 

34 

.113374 

19 

.117257 


Hence it appears that by a mean of 34 out of seventy-five experiments in 
nine different vessels, with five different liquid capacities, and composed of 
three different kinds of materials, we obtain a result not sensibly varying 
from .1134, as the specific heat of the iron standard piece between ordinary 
temperatures and 212° Fahrenheit. 

The next step in this investigation again required the use of the copper 
cylinders, but instead of the heating apparatus W being filled with water, it 
was made to contain mercury, which allowed a higher temperature to be 
given to the vessel M. This latter vessel was now filled with melted tin, 
instead of mercury, as well to avoid the inconvenience from mercurial 
fumes, as to obtain the specific heat of iron at a second fixed temperature, 
the melting point of tin. It needs scarcely be mentioned, that the same 
degree of exactness in the accordance of experiments at temperatures above 
400°, as at 212°, is hardly to be expected. Table XI. exhibits a number of 
trials made in the manner just pointed out.* A certain amount of error may 
possibly have been introduced into these experiments by the want of 
uniformity throughout the mass of melted tin; for, after withdrawing the 
standard piece and lowering the thermometer to the bottom of M, it was 
found that a difference of a few degrees, was a possible occurrence; but as 
the bulb of the mercurial thermometer, which marked the temperature of 
the melted tin, was generally kept at the same level with the centre of the 
standard piece, any difference between the two, must be trifling in amount. 

* It will be evident on a comparison of this table with those which have preceded, 
that the general law observed by Petit and Dnlong [Ann. de Chim. et de Phys. Vol. 
VII.] of an increase of specific heat by increase of temperature, when the method of 
heating water is employed, is confirmed by these results; but experiments on the 
production of vapour hereafter given, exhibit a very striking conformity, in regard 
to specific heat, with those made below 212°. 





























TABLE XI. 

Experiments to determine the specific heat of the standard piece of the steam pyrometer at temperatures above 212°— containers , tivo 
copper cylinders , weight of standard piece 6000 grains. Heating performed in bath of mercury or melted tin. 


40 


C/5 

M 

Ph 

< 

s 

w 


c 

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.O 


i 

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g 

g G 
J3 -f? 


G 

-O 

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3 


co S 


o 


S-H 

CD 

C 

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G 


o 
a> 

(O ^ 

c 

a> a 
G3 ^ 


m 

• r—4 

X 


o 

CO 


c 

o +* . 

o 5^-a 

c 

_C .5 

biDli 
3 ® 
£ 


S-, 

i >—1 

03 


O 


e 

03 

*3 

fe¬ 


ed 

a 

i-i 

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CO G 
03 

_ >»«2 
— "2 rS 
be 


03 

03 
> 

O 

rQ 

03 
o 

O r-C 

tO 

nd ® 
03 .5 
ns 
c 

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nb 
c 

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Hb 

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xs 

co 

■ a 


rj G 


G 

bio 


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£ 
o 
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.£} .£ ^ 


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cd 


Jb co 
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rG 

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r—,—i 

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G O 
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be 03 

03 O 

G -O O 
-G ^ * 

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G rG - nb & s 

s.sp| gts 2 

(*■“5 c~! QJD C k,. —4 

P 1 - G ^ o) •i-< rS 
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£ 

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r—i 

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co 

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, co 


G^s 2 

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C* *» TS-g 

~ s £ 

.S O c 5 

c -G O 


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C? 




w (ZJ 
G ^ 


co 


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♦-* o 
C3 CJ 


® o 

da +-> 


+* CO 
c 

® G 
G 0 

£■5 


(T) >-< 

O cd 
G ^ 

bo 

G 

‘S 3 
~ 3 *5 
G -O £ 


c? ~ o 2 
§ 

cf benb 

.5 •— c G 

a g c 

.5 G G 2 

nO ®*> 
C -G G 
— *j G _i_> o 
^3 ^ Gqo 

03 • 

^ S o ® -a 

O G O 

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X) 


C • / 

I L 

® °o 

£ ^ 
G 2 

•4-G C 

c *s 

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bo 

£ G 
O n3 

2 "55 
S «*“ -2 


o 

nf 


nb 

G 


f-H 

G 


2° G O G *G cd 3 
3 m O £>• • [>. G 

c 2 ~ > nb 1> c 
3 ^ ® c .a 

o £ ja g G 


C2 ^ 

cd .tS 

G ^ G 

“«S 

.3 4b 
G G 


C 

G 

a 

t 

>-i 

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CL 


•}B3i{ OTjpads 


CO 

H 


1—1 

Tf 

o 

rj< 

o 



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T—H 

I—1 



o 


<G 

• 03 

rH 

C3 

<03 


CO 

C3 

03 

CM 

03 


•pajBan jcaijura P^ojl 

grs. 

40905, 

40905, 

40905, 

40809 

39290 

39233, 

39233, 

M3JBAV Ut .T3J31U 

-ouuarp jo juaiBAinba 

grs. 

196.7 

196.7 

196.7 

100. 

100. 

43.7 

43.7 

•.xajiJAV jo jqSpAv ui .to 

-UIBJUOO JO JU3(BAinba 

grs. 

2050 

2050 

2050 

2050 

531 

531 

531 

1 

M3UIBJUOO am 

ui .taddoo jo jqSpAl 

grs. 

19718 

19718 

19718 

19718 

5168 

5168 

5168 

M3UIBJU0D 

aip m ja^BAv jo n[SiaAV 

grs. 

38659 

38659 

38659 

38659 

38659 

38659 

38659 

MajBAV aq; iq 

pauiuS a.injB.iaduiax 

p 

6.05 

9.95 

9.55 

6.75 

6.85 

6.80 

7.26 

1 

•no.it aq; 

^q 3S0i ajniB.iaduiax 

o 

332.55 

536.6 

491.7 

363.45 

367.25 

367.3 

366.74 

•uois.iauiuti 

jb iio.ii jo a.injB.iadutax 

Q 

400 

610 

560 

442 

442 

446 

450 

•ptia aqi ib 

.tajBAV jo ajnjB.iaduiax 

p 

67.45 

73.40 

68,3 

78.55 

74.75 

78.7 

83.26 

•SuiuuiSaq aqi jb 
. iajBA\ jo a.iiijB.iaduiax 

o 

61.4 

63.45 

58.75 

71.8 

67.9 

71.9 

76. 

•pua aqi jb apis 
-ut .iib jo a.injB.iadmax 

o 

67.4 

68.1 

67.7 

78. 

75.25 

81. 

81.5 

•SuiuuiSaq jb .tapuil 
-Xa jo apism •dtuax 

o 

67.6 

! 

66.8 

67.7 

75. 

75.1 

79.5 

80, 

i 

•pua jb apis 

jno jib jo a.injBaadiuax 

Q 

71. 

71. 

71. 

80. 

80, 

85.5 

86. , 

•Suiuui3aq JB ‘puqla uij 
jo apis jno .iib jo 'dtuax 

o 

71.5 

70, 

71. 

80. 

80. 

80.5 

85. 

•sjuauiuadxa aqj jo -o^ 

*-• cb "si* o co i> 
































41 


The last arrangement for demonstrating the specific heat of iron, was in 
the nature ot a verification of the methods already detailed, by means of a 
direct application of the standard piece to the purpose for which it is 
ordinarily employed—that of generating vapour instead of heating water. 

It was, for this purpose, heated as before described, in the bath of melted 
tin to such temperatures, above 212°, as were deemed necessary, and 
immediately plunged into boiling water. The effect produced, was now 
ascertained by multiplying together the weight of vapour generated, and 
the latent heat of steam; while the cause was found in the weight of iron, 
its specific heat and the temperature which it expended. The shield to 
defend the iron in transitu was employed, and the other precautions to 
avoid error were still persevered in. The results will be found in table XIII. 

Before proceeding however with the detail of those trials, it is necessary 
to state the mode of ascertaining the latent heat of the vapour of water, 
which enters as an essential element into the calculations of that table. It 
will be perceived that the principle of the method is similar to that of Count 
Rum ford. 

Apparatus for the latent heat of vapour. 

The apparatus by which the latent heat of vapour was examined, is re¬ 
presented in plate 8, in which A is a cylindrical vessel to contain water; B 
a larger cylinder formed of pasteboard, higher than the pieceding, surround¬ 
ing and defending it from the air; C is a stand of charcoal on which the 
vessel rests; D is a vessel of tinned iron 14 inches high by 9 in diameter, 
to prevent the vessel F (the same which has already been described as the 
boiler of the steam pyrometer,) from affecting by radiation the temperature 
of A. P is a sheet of tinned iron, attached in a vertical position to the edge 
of the table T, serving still further to defend A from the influence of radia¬ 
tion from the boiler or steam pipe. S is a cylindrical piece of cast iron, 
having round its lower base a ridge r, adapted to retain a hold of the 
small hook h, within the copper case L, intended to receive it when hot. 
From the upper conical part of this case rises a pipe g , | of an inch in dia¬ 
meter, curved into a semi-circle at the top to dip under water. Within the 
curved part is a stop-cock K, adapted to regulate, or entirely to prevent 
when required, the flow of steam from L. At q is an enlargement of the 
pipe g, with a funnel-shaped tube to receive the bulb of a thermometer e, 
sustained and made tight by packing around the lower part of its stem. 
The purpose of this thermometer is to mark the temperature of the effluent 
steam, iv is a handle formed by a number of folds of flannel made fast to 
the pipe, a: is a thick roll of cloth surrounding g and preventing the escape 
of vapour exterior to the tube. The thermometer o marked the temperature 
of the apartment in the immediate vicinity of the apparatus, i gave that 
within the pasteboard case, while t gave the temperature of the water in A. 

No fire was kept in the apartment where the experiments were perform¬ 
ed. The container A, when quite dry, was first accurately counterpoised 
in a scale pan, and then taken out and weights substituted to avoid any 
possible error in the scale beam. The vessel being next returned to the 
scale pan instead of the weights, was filled so nearly with water, that the 
vapour to be condensed, would make it quite full; after which a counter¬ 
poise was once more effected, and the vessel being taken to its place within 
B, the weighing by substitution was repeated, giving the sum of the weights 
of the water and of its container. The counterpoise being once adjusted 
for a series of experiments, it was only necessary in repeating the trials 
with new portions of water to replace the vessel A in the scale pans, and 


42 


pour in a fresh charge of water till the equilibrium was obtained. The se¬ 
veral thermometers were next adjusted in place, that which was to indicate 
the temperature of the water being made with special reference to these 
trials, and the weight of mercury which it contained, as well as that of the 
glass immersed in the water exactly ascertained. 

While the operations of weighing and arranging, as just described, were 
performed by one assistant, another having heated to a low red heat the cy¬ 
linder S, inserted it in the copper case L, where being retained by the hook 
/*, it was plunged into the boiling water contained in F, and the latter placed 
within D; the packing x was adjusted, and stop-cock K opened, to allow 
the air to be driven from the pipe g , and the whole apparatus, including the 
thermometer e, to be raised to the temperature of 212°. This being done, 
the apparatus was conveyed to the room where the water vessel was placed, 
and after turning the stop-cock for an instant, to expel any water which 
might have been condensed during the transit, the mouth of the pipe was 
brought briskly round and immediately plunged under the water. Here it 
was continued until the vessel A was perceived to be full, when it was 
withdrawn and the stop-cock closed, but not until the mouth was quite 
above the water. During this manipulation the thermometer t was kept 
constantly moving, to equalize the temperature of the water. This being 
done, the increase of weight was ascertained by again counterpoising the 
vessel and its contents. It is apparent that heat imparted to the w r ater, by 
the condensed vapour, must be employed for heating at least three different 
bodies, the water, the container and the thermometer t. 

It was therefore necessary to know the weight and specific heat of each, 
in order to determine the relation of the heating power of a given weight of 
steam, compared with the cooling power of a quantity of water equivalent to 
the sum of these three bodies. As the quantity of air which was included 
in the box B was small in amount, as the specific heat of air is, weight for 
weight, but about one fourth that of water, and as the experiments were 
generally performed in such a manner as to allow the air to operate partly 
in favour, and partly against the heating power of the steam, it was not 
deemed important to take into the calculation the minute quantity due to the 
cooling power of this mass of air. In a few instances however, its effects 
are noted in the column of remarks. 

The results of experiments on this subject are found in table XII. 

As the trials on specific heats below 212° had preceded those now under 
consideration, it was found convenient, to employ as containers some of 
the same cylindrical vessels which had been used in that investigation. The 
materials of each are specified in the table. The calculations are very sim¬ 
ple when we have obtained an expression for the equivalent quantity of 
water equal to the three terms above specified.* 

* The latent heat of steam was calculated by the following formula. 

Putting w — the weight of water in the vessel. 
n = that of the vessel itself. 

g = that of the glass in the immersed part of the thermometer. 
m — that of the liquid in the same. 
x — the specific heat of container. 
y — do. of glass. 

z — do. of the thermometric liquid. 

v = the weight of vapour condensed. 

T = the temperature gained by the water. 

t = the distance of the final temperature of the water below that at which 
the steam enters it, 

and / = the latent heat of vapour at the boiling point. 


/Y(//s !///. 





































































































































































































































































































































































pour 
veral 
the t( 
trials 
glass 
W 
perfo 
linde: 
h , it 
withi 
the a 
them 
the a 
and i 
migh 
brouj 
was i 
with* 
abovi 
cons 
done 
vess* 
the c 
bodi* 
It 
in O] 
steai 
the f 
in tl 
wei^ 
gem 
in fc 
deer 
cool 
are 
r I 
A 
con: 
the 
mat 
pie 
wat 

* 

P 













43 


Results of Experiments on Latent Heat. 

The accompanying table presents the determination, in the manner 
already described, of the latent heat of the vapour of water. The trials 
were made in four different cylindrical vessels, one of copper, two of glass, 
and one of sheet iron. 

The quantities of water varied from about 13000 to upwards of 39000 
grains. 

The equivalents of the thermometers were either approximately estimated 
by knowing the size and thickness of the bulbs, or were actually determined 
by weighing before and after filling, and in every instance the calculation 
for the thermometrical equivalent, was made only on the part of the instru¬ 
ment actually immersed. 

It will be perceived that three out of the four vessels, give mean results 
which differ from each other by not more than 3 degrees. The third set, 
or that made in thin glass, and which differs widely from all the rest, ought 
probably to be rejected. If this be done, the other three sets give a mean 
result equal to 1037 degrees ; which is 3.8 degrees less than that obtained 
by Count Rumford. Including the third set, the mean result will be 1026.83. 
As the steam rising up in the case L, necessarily came in contact with 
the hot iron S, it became, to a certain extent, surcharged with heat; but 
as the thermometer indicated its temperature at the moment of escape, 
an allowance is easily made for the surcharge. The rapidity of flow being 
duly regulated by the stop-cock k, the steam was prevented from carrying 
over any water in an unvaporized state. As the amount of surcharge sel¬ 
dom exceeded 3 degrees, it was not considered necessary to calculate for 
the difference between the specific heat of vapour and that of water. By 
the experiments of Delaroche and Berard, the specific heat of vapour, com¬ 
pared with that of water, is .847 to 1.000. Admitting this to be true, the 
result must, in any case which has occurred to the committee, be but little 
affected by allowing for the difference.* 

Then the heating effect is represented by T x (w 4- nx + gy + mz )i an( l 
the cooling effect by v X (/ + 0» whence v x (1+ 0 = T X (w + nx -f gy + mz) 

and consequently l =—----— t. 

* The experiments hitherto published, had left some doubt as to the true latent 
heat of vapour. Black first obtained the number 810°; Watt afterwards gave it 
95C° ; Southern produced 945 ; Lavoisier made it rather more than 1000° ; Rumford 
1040.8; Despretz 955.8; Ure 1000; Thompson “more than 1000°.” Watt and 
Clement have both established the position that the latent heat of steam, added to 
the sensible heat above 32°, is nearly a constant quantity. As, however, the point 
32° is entirely arbitrary, and as no temperature is now known , at which vapour does 
not rise from water or ice, there is reason to suppose that in strictness, th6 
constant—if there be one—is different from that which these experimenters have de¬ 
rived. If not, the latent heat of vapour must diminish below 32° as the temperature 
diminishes. 


4 * 




44 


TABLE XIL 

Experiments to determine the latent heat of Steam , employing \ 
a given weight of water in a vessel of known weight and specific $ 


No.of Experim’t. 

DATE. 

Kind of vessel 
which contained 
the water. 

Temp, of air out¬ 
side at beginning. 

Air outside at 
the end. 

Air inside of the 

box at beginning. 

Air inside at the 
end. 

Temp, of the 

water at begin¬ 

ning. 

Temp, of water 

at the end. 

Gain of temp. 

by the water. 

| Weight of va- 
| pour condensed. 

Weight of water 

in the container. 

1 

Equivalent of 

the thermometer. 

Weight of the 

container. 




o 

o 

O 

o 

o 

o 

o 

grs. 

grs. 

grs. 

grs. 

1 

r~ 

^ s 

M' Ot 

00 • 

thin 

coppei 

84. 

85. 



75.35 

86.1 

10.75 

347 

38659 

100 

5178 

2 

(( 

(< 

83. 

83. 



70.9 

85.75 

14.85 

504 

38659 

100 

5178 

3 

ft 




72.25 

72.6 

68.75 

75.75 

7. 

241 

39305 

30 

5178 

4 

(( 

« 

• 


72.60 

73. 

70. 

77.25 

7.25 

250 

39305 

30 

5178 

5 

ft 

* 

thick 

glass 

80.45 

80.67 

78.5 

82. 

74.6 

92.65 

18.05 

299 

17112 

43 

12272 

6 

ft 

ft 

80.85 

81. 

81. 

82. 

75.5 

88. 

12.5 

192 

17112 

43 

12272 

7 

Sep. 19, 

u 

67.5 

67.55 

68. 

68. 

64.6 

74.5 

9.9 

156 

17428 

7.3 

12272 

8 

tt 

ft 

67.7 

67.7 

68. 

68. 

65.25 

73.25 

8. 

127 

17428 

7.3 

12272 

9 

Sep. 12, 

thin 

glass 



73.4 

73.6 

68.5 

78.5 

10. 

167 

18405 

30 

2986 

10 

11 

Sep. 26, 

Sep. 5, 

tt 

thick 

sheet 

iron 

60.4 

81.1 

60.7 

81.15 

60.5 

81.5 

61. 

82. 

58.5 

75.1 

68.5 

89.2 

10. 

14.1 

156 

169 

17428 

13152 

7.3 

43 

2986 

5167 

12 

ft 

C( 

81.4 

82.6 

81. 

82. 

73.7 

89.8 

16.1 

190 

13152 

43 

5167 








































45 


TABLE XII. 

heat , to receive and condense the vapour as it passed from the 
mouth of the p)ipe. 


Equivalent of 

the container. 

i Total equiv. of 

matter heated, es¬ 
timated in grains 
of water. 

Weight of water 
X gain of tempe¬ 
rature. 

| W X T 

* 

Temp, of steam 

on enter’g water. 

Sensible heat lost 

by the steam. 

grs. 

grs. 



o 

o 

O 

540. 

39199. 

421389. 

1214. 

214 

127.5 

540. 

39199. 

582005. 

1154.7 

215 

129.25 

540. 

39875. 

279125. 

1158.2 

215 

139.25 

540. 

39875. 

289094. 

1156.3 

214 

136.75 

1342.5 

18507.5 

334060.4 

1117.25 

213 

120.35 

1342.5 

18507.5 

231343. 

1204.82 

\ 

215 

127. 

1227. 

18662.3 

184756.7 

1184.3 

214 

139.5 

1227. 

18662.3 

149298.4 

1175.5 

213 

139.75 

299. 

18734. 

187340. 

1121.8 

213 

134.5 

299. 

17734.3 

177343. 

1146.8 

212 

143.5 

586. 

13781. 

194312.1 

1150. 

213 

123.8 

586. 

13781. 

221874.1 

1167.7 

214 

124.2 


■° 53 

« S' 

oj 

•C 

a 


CW 

—■ w 

5 a 

a. 

® a 

co C 


1086.5 


1025.5 


1018.95 


1019.55 


996.9 


1077.82 


1044.8 


co 


* § 

<L> CO W 

r* -r" 

^ U co 

4-» 2 •*-* 

c fa 
S3 g ® 

p s li 
OS T3 


REMARKS. 


1037.87 


1035.75 


987.3 


1003.3 

1027.2 

1043.5 


1038.5 


995.3 


1035.35 


The equiv. of 
the therm, which 
marked the temp 
in first 2 expts 
is only estimated 
approximately. 

This expt. was 
made w ithout the 
use of a 2d cylind. 
to defend the wa¬ 
ter vessel,and as it 
ended but little 
above the temp, of 
the air, the result 
must be somewhat 
too high. 


< 


The time requi¬ 
red to bring the 
water to a perfect 
state of uniformi¬ 
ty in temp, after 
the steam was cut 
. off, and the excess 
of its final temp 
above that of the 
air,caused a slight 
error in defect, 
The containerwas 
surrounded by 
pasteboard box. 

- This expt. termi 
nating more than 
10° above the air 
is evidently to be 
rejected for de 
feet. The rise of 
temp, in the box 
proves this to be 
k.the case. 

The pipe was 
withdrawn from 
the water befor 
closing the stop 
cock, in order to 
prevent the rush 
ing up of water 
Do. Therm 
very small, but 
with along stem to 
extend nearly to 
the bottom, form 
ed of 59 grains of 
glass, & contain 
ing 42 1-2 grs. of 
mercury. 

Do. 


The bulb of the 
therm, estimatec 
approximately. 

This expt. termi 
nated 8° above the 
initial temp.of the 
air in the box, and 
began only 2° be¬ 
low it,consequent¬ 
ly lost some heat. 
& gives a result 
rather too low. 







































46 


Specific Heat by Vaporization. 

Having determined the latent heat of vapour, it is not difficult to verify 
our preceding determinations of the specific heat, by operating in precisely 
the same manner as we do to obtain the temperature of a body,—except, 
that the temperature of the bath of melted metal is now first ascertained by 
the mercurial thermometer; and the actual temperature of the standard 
piece being then known, is compared with the weight of vapour which 
it produces, by cooling in boiling water from its initial temperature 
down to 212°. These experiments were made both before and after the 
screw beam and counterpoise were changed. The weight of the standard 
piece is, in both cases, taken in degrees of the pyrometer scale as existing 
at the time. 

It will be seen, that, assuming as correct the determination of latent heat, 
made bv the committee (1037°), the experiments given in the accompanying 
table (No. XIII.) afford results for the specific heat of iron as follows:— 

1. Taking the mean of 29 experiments, it is . . , .11325 

2. Taking only those made before the screw beam was 

changed, (9 experiments,) we obtain . . . .11340 

3. Taking together the last 20 experiments of the table, we 

have . . . . ..... .11324 

4. Experiments Nos. 7 and 8 with the first screw and coun¬ 
terpoise, differing only in the 5th place of decimals, give .11336 

5. Six out of the last 20, differing only in the fourth place, 

give ......... .11356 

6. The mean result of these 5 comparisons, is . . .11336 

As a mean of the nine sets of experiments in different vessels, the specific 

heat below 212°, determined by heating water, as above detailed, was 
found=. 113374. As the calculations just detailed are carried only to the 
5th place, the two results may be considered as differing from each other 
only by —1-^th part of the total value. 

Of those experiments which differ considerably from the general result, 
about the same number was found above, as below the mean , showing that 
if these discrepancies be due to errors of observation, they are, as we 
ought to expect, liable to be either in excess or defect; and that they coun¬ 
terbalance each other. 

The eight experiments, of which the results differ only in the 4th place 
of decimals, were made at temperatures varying from 392 to 595, without 
indicating any decided difference in the specific heat of the metal within 
those limits. 

Of the extreme results in the table, the highest was obtained at 480° and 
the lowest at 488°;—the next to the highest, at 500°, and the next to the 
lowest, at 292°. 

From the exact conformity of the general results of the method of evapo¬ 
ration, and that of heating water, in trials below 212°, it appears that if the 
specific heat, of the standard piece be determined by the latter method, and 
its weight be duly regulated to conform to the length of the threads of the 
screw beam,—and to the weight of the revolving counterpoise, its indica¬ 
tions of temperature will be such as to connect themselves immediately 
with those of the mercurial thermometer. 



47 


TABLE XIII. 

-Experiments to determine the specific heat of the standard-piece of wrought 
iron used in experiments with the Steam Pyrometer during this inves¬ 
tigation. The heating performed in a hath of mercury or melted tin , 
and the effect measured by the weight of vapour carried off in cooling , 
from the first observed temperature down to 212 °. 




Cm 

O 

<y 

JS 

e> 

3 

a 

• (H 

r* 

> u 
y o 

3 « 

Cm 

O 

CO 

•*-> 

cs 

<v 

£ 

o 


m 

1) 

£ 

•g 

CL 

* 

W 

gj 

-C 

m 

Cm 

O 

• 

o 

DATE, 

Observed temperatur 
ie iron. 

£ 

3 

a 

V 

•4-> 

CO 

Cm 

O 

w 

-CJ 

£ M 
o 

Temp, lost by the ire 
e generation of steam. 

Weight of the stanc 
ece in pyrometric uni 
■grees. 

jo 

X 

L 

« 3 

bt> u 
•jr a> 

£ eu 

? s 

Weight of steam X la 
at (=1037°.) 

Specific heat of iron 1 
e preceding data. 

REMARKS, 

fc 



C/i 

<v 

pC 

. — O 

evd 

QJ 

0> 




1833. 

o 


o 





In the first nine experiments 

1 

July 20, 

600 

390 

388 

9065.7 

3517491 

404430 

.11494 

the heating of the standard- 

2 

tt 

584 

366 

372 

9065.7 

3372440 

379542 

.11253 

piece took place in the heating 
apparatus used in trials on the 










metals, and the shield to defend 

3 

July 27, 

562 

351 

350 

9051.4 

3167990 

363987 

.11478 

it in passing to the boiler was 
not employed. 

4 

<( 

556 

334 

344 

9051.4 

3113881 

346358 

.11123 

5 

(t 

510 

280 

298 

9051.4 

2697317 

323544 

.11995 


6 

<( 

576 

351 

364 

9051.4 

3294709 

363989 

.11047 


7 

J t 

590 

374 

378 

9051.4 

3421429 

387838 

.11335 


8 

it 

595 

379 

383 

9051.4 

3466686 

393023 

.11337 


9 

tt 

462 

240 

250 

9051.4 

2262850 

248880 

.10998 

r In this experiment the ther- 

10 

1835. 



238 





mometer attached to the boiler 
had fallen 2 or 3° before the con- 

June 5, 

450 

278 

10443 

2485434 

285500 

.11487 

< denser was put on. In this and 









the eleven following experi¬ 
ments the heating was perform- 











Led in a bath of mercury. 

11 

tt 

466 

280 

254 

10443 

2652522 

290360 

.10946 


12 

tt 

454 

273 

242 

10443 

2527206 

283101 

.11589 


13 

tt 

470 

480 

295 

333 

258 

268 

10443 

10443 

2694294 

2798724 

305915 

.11350 

r The condenser kept off till 

14 

tt 

345321 

.12338 

5 the thermometer had fallen a 
C little. 






15 

ft 

488 

325 

276 

10443 

2882268 

337025 

.11693 

^ Condenser put on sooner than 
^ in the preceding case. 

16 

June 13, 

476 

302 

264 

10443 

2756952 

313174 

.11359 


17 

ti 

435 

260 

223 

10443 

2485434 

269620 

.10848 


18 

.< 

462 

287 

250 

10443 

2610750 

297619 

.11399 


19 

ft 

444 

262 

232 

10443 

2422776 

271694 

.11200 


20 

ft 

392 

205 

180 

10443 

1879740 

212588 

.11307 


21 

22 

ft 

292 

83 

80 

10443 

815440 

86071 

.10555 

.11374 

r In this and the following expe- 

June 20, 

535 

370 

323 

10443 

3373089 

383690 

< riments a bath of tin w as employ- 










C ed to heat the standard-piece. 

23 

tt 

490 

307 

278 

10443 

2903154 

318353 

.10965 

24 

tt 

500 

350 

288 

10443 

3007584 

362950 

.12067 


25 

tt 

492 

320 

280 

10443 

2924040 

331840 

.11348 


26 

tt 

492. 

310 

280 

10443 

2924040 

321470 

.10994 


27 

• t 

492. 

330 

280 

10443 

2924040 

342210 

.11703 


28 

tt 

492. 

325 

280 

10443 

2924040 

337025 

.11526 


29 

ft 

488 

290 

276 

10443 

2882268 

300730 

.10433 






Mean of 29 Experiments 

.11325 








































4S 


Heating and cooling oj liquids. 

In determining the specific heat of the iron standard-piece, it became 
evident that the influence of the air and other extraneous objects upon the 
temperature of the vessel of water could not be omitted, at least while the 
experiments were conducted, without enclosing the container in some other 
vessel which might shield it from the radiating and conducting power of 
surrounding bodies. 

But in order to neutralize, as far as practicable, the disturbing influence of 
the causes just mentioned, it was evident that with a given state of the air 
and of other bodies, the water-vessel must be made to receive during an ex¬ 
periment as much heat from surrounding objects as it imparted to them. 
This could be effected only by commencing each experiment, so much be¬ 
low the temperature of the air, that, during the cooling of the iron in water, 
the temperature of the latter should, in rising, pass through the temperature 
of the air, and not only rise above it, but so divide the duration of the ex¬ 
periment that the cooling effect of the air in the latter portion of time should 
precisely equal its heating influence in the former. 

It, therefore, became necessary to discriminate between the respective in¬ 
fluences of hot iron and of the air, in order that the temperature of the wa¬ 
ter might be adjusted to that of the apartment before commencing the ex¬ 
periment. 

By an examination of table XIV. it will be perceived that in twenty-three 
different experiments the times of rising through different stages of tempera¬ 
ture are given, together with the initial and final temperatures of the air 
and of the water. It will not fail to be observed, that in comparisons of 
this nature, the materials and construction of the thermometer are elements 
of quite as much importance as the quantity of liquid heated, or the materials 
and other circumstances of the container. 

Thus, it will be seen, that by a mean of 8 sets of observations in which 
the mercurial thermometer A (calculated to be equivalent to 152.7 + 43.45) 
= 196.15 grains of water, was employed, the time required to obtain the 
full effect of 6000 grains of iron heated to 212°, and cooled in water at 60 
or 64 degrees, was 148 seconds. 

The quantity of water was varied from 12000 to 18000 grains. 

With the mercurial thermometer B, estimated at about 43 grains of water, 
the time by 7 sets of observations was found to be 126 seconds; the quan¬ 
tity of water from 13000 to 20000 grains, and the vessel either of glass or 
sheet iron; the two latter circumstances serving to produce comparatively 
little effect on the time required to bring the temperature to a stationary con¬ 
dition. 

With the spirit thermometer C, 8 sets of observations gave a mean dura¬ 
tion of 295 seconds, the weights of water varying from 13000 to 18000 grs., 
and the container being either iron, weighing 1733 grains, or glass weigh¬ 
ing from 2,900 to upwards of 12,200 grains. This last thermometer has a 
bulb OyL inches in length, and .5 inch in diameter, weighing 264 grains; 
and contained about 142 grains of alcohol, which, by the mean of 8 different 
^terminations,* has a specific heat of .641, and consequently is equivalent 
to 91 grains of water, and the glass to 26.4 grains, whence the whole por¬ 
tion immersed was equivalent to 117.4 grains of water. 


*See Thompson on heat p, 76. 


49 


TABLE XIV. 


. Synopsis of twenty-three sets of observations in six different series on the rate of heating 
in given quantities of water, by the cooling oj the iron standard-piece weighing 6000 grams 


1st Series in thin glass jar weighing 3325 

grains — Water 20432. 

2d Series in an iron jar weighing 1733 grains. 
Water 13065. ° 

S..SS 

8 

o rS 4/3 

w QJ 

. -M r 
A*-* 

® g®° c 
cv 3 "? *2 

+■> 

. a 

%-* » > 

© c3 > 

i i • 

QJ U QJ 

^ C/5 

a 

p. of 

r the 

ves- 

Cu • f • ■ 

o jo o a 

a; a 

*•3 

- a 

N-» < > 

O ctf ^ 

• •• 

QJ U V 
© C/5 

. T3 

No. of 
& pla< 
specif, 
series. 

Tern 
air nea 
water 
sel. 

Tem 
wat. at 
and en 
observs 

s«.a 

PS 

<D a 

£ tj i< 

h sf 

— a 

No.of i 

& plat 

specif. 

series. 

Tem 

air nea 

water 

sel. 

Temj 

wat. at 

and en 

observa 

Rise 

temper, 

ture in 

Time 

lapsed 

ing the 

1 

61.9 

54.5° 

.5° 

24" 

1 

65.5° 

60.8° 

1.2° 

16" 

« • 

1> cm 


Ther. 

1. 

8 




1. 

6 

i-H CM 


B. 

1. 

13 



Ther. 

1. 

3 

• • 

XI c. 


Mer- 

2. 

30 

• 

r-H 


B. 

1 . 

O 

O 

c3 X 

h W 


curial. 

.6 

44 

X 

W 


Mer. 

1. 

1 . 

3 

4 








Result. 

61.9 

59.6° 

5.1 

119 

■—/ 

I—i 



1. 

.4 

.1 

5 

4 

5 

2 

63.5 

60. 

2. 

17 

> 



• 

co 


Ther. 

1. 

15 




.1 

6 

CM 


B. 

1. 

12 

h 



.2 

11 

X 



.4 

30 




.1 

17 

w 



.1 

8 




.1 

15 

> 



.1 

7 




.1 

19 




.1 

.1 

< 






cS 



10 

Result, 

66. 

69.1 

8.3 

117 

h 



.1 

45 



■—-- 







2 

68.25 

59.9 

Ther. 

2.1 

2. 

“21 

11 

Result. 

63.5 

64.9 

4.9 

149 






CM 


B. 

1. 

1. 

8 

13 

3 

63.5 

64.9 

1.1 

19 

X 

W 




Ther. 

1. 

4 



.4 

7 

!> ^ 


B. 

1. 

7 




.4 

9 

—i CM 



1. 

12 

£ 



.2 

10 

■g X 

h w 



.3 

.1 

19 

11 

X 

cS 

L_l 



.1 

.1 

9 

11 




.1 

22 




.1 

10 

Result. 

63.5 

69.5 

4.6 

94 

Result, 

69.5 

67.3 

7.4 

109 

4 

71. 

67.1 

.9 

19 


52.5 

50.6 

.4 

20 



Ther. 

1. 

8 



Ther. 

1. 

10 

V) 

CM 


B. 

1. 

8 



C. 

1. 

16 



.5 

8 



Spirit. 

1. 

12 

X 



.3 

7 




.4 

7 

W 



.2 

6 



c 

.2 

5 

• 

> 



.2 

.2 

15 

9 



lff5 

.2 

.2 

4 

4 




.2 

17 

CO 



.2 

2 

f 



.15 

30 

M 



.2 

13 




.05 

18 




.2 

2 









.2 

.2 

4 

Result. 

73. 

71.8 

4.7 

145 

H—< 



7 








.2 

5 

5 

71. 

67.1 

.9 

15 

X 



.2 

6 

to 


Ther. 

1 . 

8 

C3 

h 



.2 

9 

CM 


B. 

1 . 

14 




.2 

8 

• 

X 



1 . 

18 


> 


.1 

13 

a 



.2 

14 


A 


.1 

5 

• 

> 



.3 

19 




.1 

12 

i—* 



.2 

29 




.1 

11 

cs 



.05 

14 




.1 

17 

h 



.05 

22 




.1 

.08 

28 

31 

Result. 


1 






72.5 

71.8 | 

4.7 1 

153 

Result, 

52.5 

57.58 

6.98 

251 


QJ 

V 

bO 

QJ 

C4 

H 

(X 

so 

a 

• pH 

qj 

f0i 


%-1 

o 

QJ 


QJ 

a. 

S 

QJ 

•M 

QJ 

5 


& 

QJ 

& 

O 

tc 

• F-l 

o 

0> 


o 


bf) 


QJ 

> 














































































































































SO 

TABLE XI Continued. 


3d series in a glass jar weighing 2996 grains.—Water 16947. 


*S C £ 
£V- 2 

S 

0/ 1 

0/3 8 
• *■* 2. 

ft* ■ « 

O fcoo d 
ft-2’3 « 

Lm i 
° 2 * 

* • • 

QS U <V 
~3 cr 

4,-e’C 

JCd 
O.- 2 
£ OrfS 

rtj 1 

O £ <« 

W -fl (1» 

• ♦-» > 
o.t, 

® Sfo B 

O « ? 

i i • 

QJ U & 
i/5 

<U 

's.«as r 

° £ u 

d « 

01 d fc 
h £ 

£ 3 £ > 

D . 

H tj-o 8 

8g,S 
rt e a 

E-di 

V" o> 5 

H £,&«> 

No.ofi 

& plac 

specif. 

series. 

ft rt , 

C n; 

0) - 0) 

‘ S* cl >LI 

i*8fc 

H S-gJ 

% «J s 
.2 p« r 

PS s g 

S’Sl 

H S.u> 


'« if « 

!> C3 O 

<i> s 

4-> 4-> 

« s 

«—■ >H 

*8 k 8 

* g-§ 

QJ SJ 

■*-» 4-» 

«.5 

1 

57.5° 

56.90° 

.91° 

25" 

Brought 



4.17° 

87 " 


Ther. 

1. 

15 

forward. 



.5 

15 



C. 

1. 

20 




.2 

11 



Spirit. 

.5 

10 




.2 

13 

% 


.5 

12 




.1 

9 

rH 



.5 

14 

w 



.1 

9 

4-- 

CL 



.2 

7 

• 



.1 

11 

X 

pq 



.2 

7 




.1 

15 


• 


.2 

9 




.1 

19 

M 



.1 

1 

SB 

h 



.1 

34 

4 > 



.1 

8 




.11 

26 

3 

c 5 



.1 

7 






h 



.1 

5 









.1 

8 

Result, 

57.5 

58.11 

5.78 

249 




.1 

6 









.1 

7 

4. 

56.5 

49.35 

.65 

15 




.15 

24 



Ther. 

1. 

13 

Result. 

58. 

61-95 

5.86 

185 



c. 

1. 

1. 

14 

18 

22 

2 

58.5 

52.62 

.38 

13 



1. 



Ther. 

1. 

14 

W 



1. 

27 



C. 

.5 

10 

l-J 



.1 

10 




.5 

9 

r* 



.1 

11 




.5 

11 




.1 

13 




.5 

12 

o 5 

h 



.1 

22 




.5 

11 




.1 

31 




.2 

4 




.1 

63 

ci 



.2 

7 




.06 

205 

cL 

* 



.2 

.1 

8 

2 

Result, 

56.5 

55.66 

6.31 

464 

W 



.1 

5 

5. 

67.2 

63.51 

.49 

16 

• 

k -4 



.1 

6 



Ther. 

1. 

7 




.1 

6 



A. 

1. 

7 

3 

c« 



• 1 

5 



Mer. 

1. 

10 

h 



.1 

7 

W 



1. 

13 




.1 

5 

k-« 



.5 

11 




.1 

8 

> 



.5 

28 




.1 

11 

-O 



.1 

18 




.1 

10 

h 



.1 

33 




.1 

.1 

.1 

13 

18 

25 




.02 

11 




Result, 

67.5 

69.22 

5.71 

154 




.1 

.2 

46 

59 

6. 

67.1 

63.5 

Ther. 

A. 

.5 

1. 

1. 

1. 

1. 

15 

8 

7 

Result. 

59. 

58.7 

6.08 

325 

VO 


3 

57. 

52.33 

.67 

19 

W 



9 

15 

• 


Ther. 

1. 

14 

£ 



.5 

14 

> CO 


C. 

1. 

16 




.5 

27 

Tab. 

Ex. 



.5 

.5 

10 

15 

Tab 



.1 

.1 

13 

19 




.5 

13 




.06 

30 

up. 



4.17 

87 

Result, 

68.2 

69.26 

5.76 

157 





















































































































51 


TABLE XIV,— Continued. 


4th series in glass jar weighing 12272 grains.—Expts. l, 2,3,4, water 18158. Experiment 5, 

water 17902. 


o. of expt. 
place in 
ecif. heat 
ries. 

o i « 

• ~ > 

*£ c3 

T* & Sx 
^ S3 0> 

h r ^ • 

Temp, of 
at. at be g. 
id end of 
iservat’n. 

Rise of 
mp ent¬ 

ire in wat. 

Time e- 

psed dur- 

g the rise. 

o. of expt. 

place in 

ecif. heat 

ries. 

Temp, of 

rnear the 

iter ves- 

1. 

Temp, of 

at. at beg. 

id end of 

iservat’n. 

Rise of 

mpera- 

ire in wat. 

Time e- 

psed dur- 

ig the rise. 

5*2 

•3 *1 

£ c3 *© 

X- =3 

w <-> 

jr3 a 



is « o 


a e 

1 

58.75° 

52.62° 

.38° 

16" 

3 

57 . 75 ° 

52.33° 

.67° 

21" 



Ther. 

1. 

10 



Ther. 

1. 

14 



C. 

1. 

17 



C. 

1. 

19 



Spirit. 

.5 

11 




1. 

26 



.5 

13 

• 



.5 

15 




.5 

12 

CO 



.5 

20 




.5 

16 

W 



.3 

20 




.2 

9 




.1 

9 




.2 

12 




.1 

13 

w 



.1 

8 

JO 



.1 

15 

> 



.1 

7 

h 



.1 

21 



.1 

9 




.05 

23 

_D 

et 



.1 

12 




.05 

24 

r* 



.1 

.1 

16 

29 




.03 

79 












.1 

.005 

77 

39 

Result, 

uncer. 

57.83 

5.50 

319 




“ 

67.1 

63.5 

1.5 

24 






• 


Ther. 

1. 

5 








A. 

1. 

9 






X 


Mer. 

1. 

17 

Result, 

58.5 

58.105 

5.485 

313 

> 


.7 

.1 

25 

12 

2 

57. 

56.09 

.91 

~ 

-O 



.1 

20 



Ther. 

1. 

1. 

13 

18 

H 



.04 

23 



C. 

Result, 

68.5 

68.94 

5.44 

135 

.5 

.5 

.5 

14 

13 

15 

• 



5 

67U~ 

63.52 

.48 

18 

C4 



.5 

28 



Ther. 

1. 

6 

X 

a 



.1 

12 



A. 

1. 

6 




.1 

7 




1. 

9 




.1 

9 

eo 



1. 

14 

_n 



.1 

11 

X 



.4 

12 

cG 

r 

r- 1 



.1 

15 

I"** 



.1 

4 




.1 

23 

> 



.1 

5 




•05 

10 

-C 



.1 

5 




.05 

39 

Lh 



.1 

10 




.01 

37 




.1 

18 








.05 

27 









.02 

23 

Result, 

58.25 

61.71 

5.62 

290 

Result, 

67.7 

68.97 

5.45 

157 


% 


5 













































































52 


TABLE XIY.— Continued. 


5th series in a glass jar weighing 6923 grains.— Water 11764. 


No.of expt. 
& place in 
specif, heat 
series. 

Temp, of 

air near the 
water ves* 
sel. 

Temp, of 
wat. at beg. 
and end of 
observat’n. 

Rise of 

tempera¬ 

ture in wat. 

Time e- 

lapsed dur¬ 

ing the rise. 

No.of expt. 

& place in 

spe^if.heat 

series. 

Temp, of 

air near the 

water ves¬ 

sel. 

Temp, of 

wat. at beg. 

and end of 

observat’n. 

Rise of 

tempera¬ 

ture in wat. 

Time e- 

lapsed dur¬ 

ing the rise. 

1 

65.2° 

o 

d 

<o 

l.° 

10" 

3 

65.° 

60.01° 

.99° 

12" 



Ther. 

1. 

5 



Ther. 

3. 

15 



A. 

1. 

5 

m 


A. 

1. 

6 



Mer. 

1. 

6 

VO 



1. 

7 




1. 

6 

M 



1. 

9 




1. 

7 

HH 

• 



.5 

8 




1. 

11 

NH 



.5 

12 

W 



.5 

9 

> 



.1 

5 




.5 

17 

ja 



.1 

6 

> 



.2 

13 

h 



.15 

10 

x> 



.1 

14 




.08 

35 

a 

h 



.06 

34 











Result, 

65.3 

68.38 

8.37 

125 






6th series in a thin glass jar, weighing 2469 







grains—water 

,2243. 







1 

66.1 

60. 

1. 

11 

Result, 

65.7 

68.36 

8.36 

137" 



Ther. 

1. 

6 








• A 

1. 

6 

2 

65.9 

60.02 

.98 

10 



1. 

7 



Ther. 

1. 

5 




1. 

8 



A. 

1. 

5 




1. 

12 




1. 

5 

o 



1. 

14 




1. 

5 

r-i 



.2 

3 

»o 



1. 

8 

k 



.2 

4 

% A 

M 



1. 

10 

W 



.1 

3 




.5 

9 

M 

h-H 



.1 

3 




.5 

17 

> 



.1 

10 

> 



.1 

6 

ja 

d 



.2 

14 

ja 



.1 

9 

h 



.1 

4 




.07 

52 




.2 

11 









.1 

7 









.1 

10 









.1 

21 









.06 

29 

Result. 

65.7 

68.27 

8.25 

141 i 

Result, 

66.3 

68.56 

8.56 

183 


A circumstance which deserves attention in examining this table, is, that 
a few hundredths of a degree in rise of temperature, often required, at 
the commencement of an experiment, a much longer time than in the 
periods immediately following. In fact, it was sometimes observed, that 
the plunging of the hot iron into the water, was accompanied by an instan¬ 
taneous minute depression of the liquid in the thermometer; subsequent to 
which, a stationary period occurred, and then a rapid rise—as indicated by 
the observations in the accompanying table. This phenomenon is to be 
ascribed to the sudden expansion of the glass composing the bulb of the 
instrument, by the first impression of the heat, affording an enlarged cavity 
for the liquid, before the latter begins to feel the same influence, and con¬ 
sequently to expand. This effect is the more striking, the greater is the 
difference of temperature to which the instrument is suddenly exposed. It 
needs hardly be mentioned that the opposite effect of a rise in the liquid, 






































































53 


accompanies the sudden immersion of the thermometer in a mass of fluid 
colder than itself. 

It is also worthy of remark, that the time required by the thermometer 
to attain the same final temperature as the liquid in which it is plunged, is 
greater than that employed by the iron in giving up its excess of heat to 
the same liquid. This will generally require some deduction from the 
total observed time, in order to arrive at the true time of cooling of the 
standard piece. 

The deduction will be less, the more sensible is the thermometer. Ex¬ 
periments with thermometer B, require less correction than those made 
with A, and the latter less than those with C. 

Owing to the fact just stated it is not always easy to determine the 
precise moment when observations ought to cease; consequently, the last 
rise noted may, for our present purpose, often be rejected, when the amount 
observed does not exceed 5 or 6 hundredths of a degree, and the remaining 
time taken as the true duration of the cooling. By the aid of these ob¬ 
servations, we shall be enabled to determine, very nearly, the relation 
between the respective augmentations of temperature in the water, and 
the times in which they severally occur. The more exact determination 
would require that the standard piece and the thermometer should be either 
both rapidly moving, or both at rest in the same relative positions, for 
every experiment. It was easily perceived that no slight influence might, 
in the earlier parts of the process, be ascribed to these circumstances. 

An inspection of the table, shows that the general relation to which we 
have referred, is such, that two-thirds of the change of temperature in the 
water , occurs during the first-third of the entire period of observation 
This supposes the proper correction to have been applied to the latter as 
above pointed out. 

Thus in experiment 3, table VIII., thermometer C gave a change of 
temperature 6.98°, two-thirds of which is 4.66°. During the time of the 
10th observation, the rise of temperature came to 4.66°, and the time then 
elapsed was 84" from the beginning, the whole time being 251". Dif¬ 
ference .33". 

In table VI., experiment 3, with the same thermometer, we have a total 
rise of 5.78° in 249". Two-thirds of 5.78° is 3.85°, and one-third of 249" 
is 83". It appears that a rise of 3.85° had been attained during the 
sixth observation, and that at the moment when this took place, the time 
elapsed was 78.7". Difference 4.3" 

Again in table V., experiment 2, with the same thermometer, the total 
time was 290"; but the last observation gave a change of only of a 
degree in 37". This being omitted, we have the time 253", and the change 
5.61°, two-thirds of which is 3.74°. One-third of the time is 84.3". The 
observations prove that a rise of 3.74° took place during the 5th observation 
when the total time elapsed was 79.58". Difference 4.72". 

When thermometer A was used, in experiment 5, table VI., a gain of 
5.71° took place in 154". The last T |- of a degree required 11"; this being 
omitted, we have 5.69° in 143". Two-thirds of 5.69 is 3.78; which by 
observation was attained in 44", whereas the calculation would give 47.6". 
Difference 3.6". 

With the same thermometer used in experiment 10, table VII., it appears 
that the total time, exclusive of 29" taken up in rising through the last T A__ 
of a degree, was 154", one-third of which is 51.3". The total rise in this 
time was 8.5°, two-thirds of which is 5.67°, which by observation was at¬ 
tained in 46". Difference 5.3'\ 


54 


The thermometer B, of which the action was more prompt than that of 
either of the others, gives results more nearly agreeing with the law above 
stated. Thus in table IV., experiment 24, we find a rise of 4.6° in 94". 
Two-thirds of 4.6° is 3.06°, and one-third of 94" is 31.3". By observation 
3.06° had been attained in a trifle less than 30". Difference 1.3". 

Again, in table VIII., experiment 2, a rise of 7.4° took place in 109", one- 
third of which is 36.3". The observation shows that a rise of 4.72° had 
been attained in 37". Difference .7". 

If in table VII. experiment 4, thermometer A, we omit the time of the 
last observation, we have a gain of 8.36° in 103".—Two-thirds of 8.36° 
is 5.57°, this rise of temperature had occurred at the end of 35" by ob¬ 
servation—whereas by calculation we should have 34.3". Difference .7". 

In table VII. experiment 5, we obtained a gain of 8.25° of temperature 
in 141". Two-thirds of 8.25° is 5.5°. This last number of degrees had 
been gained by the water about the middle of the 6th observation, or when 
the time from the commencement was 34". As the last of a degree 
required 52", we may safely attribute to the sluggishness of the thermome¬ 
ter the same retardation as in the preceding experiment; in which case we 
should have the total time 107", one-third of which gives the calculated 
time for a rise through two-thirds the range equal to 35.6", and the differ¬ 
ence between the observed and the calculated times=1.6". 

In table VII. experiment 6, two-thirds of the gain of temperature was 
observed to have taken place at the end of 37". The total time during 
which observations were made, was 125", and as this time is much less 
than either of the two preceding, we may suppose that a less allowance is 
required for the tardiness of the thermometer, in consequence, perhaps, of 
more rapid agitation in the liquid while the latter received its augmenta¬ 
tions of temperature. Hence if we deduct 15" we have remaining 110, 
one-third of which is 36.6" for the calculated time of attaining two-thirds 
of the gain of temperature. Difference A". 

In table IV. experiment 25, we found that a gain of 4.7° was effected in 
145", the last 18 of which were taken up in raising the thermometer B. T |.^ 
of a degree. Omitting this period, we have a remainder of 127", one-third 
of which is 42.3". Two-thirds of 4.7° is 3.14°, which, on inspecting the 
column of rise of temperature, we find was produced in 38.8" from the 
time of beginning. Hence the calculated exceeds the observed time 
bv 3.5". 

w 

Of these eleven comparisons it will be observed that eight give the time 
by observation for two-thirds rise of temperature less, by a small amount, 
than one-third of the total time, while the others give the former greater 
than the latter quantity. The mean result, however, is a difference of 
only 1.5". The results might probably be found to conform more exactly 
to the law, if the liquid were indefinite in quantity, and its rise indefinitely 
small, compared with the number of degrees through which the iron 
cooled. 

Heating by Contact of Air. 

The result just obtained, combined with another on the rate of heating of 
the vessels of liquid exposed to the action of air, will show on which of the 
experiments the greatest reliance is to be placed, as exhibiting the true 
specific heat of iron, without requiring a deduction for the influence of air. 


55 


The manner of performing these experiments, has been already adverted 
to. It consisted merely in filling the cylinders with water of a low tem¬ 
perature, and inserting in them, the same thermometers which had been 
used in experiments on specific and latent heat; placing other thermometers 
outside of the cylinders, to mark the temperature of the air. 

The time of arriving at, and of leaving each mark on the scale, was then 
noted; and the mean taken as the point of time for attaining each degree. 

Table XV. contains the result of these observations. The first 9 are, 
perhaps, from the particular attention directed to them, deserving of the 
most confidence, and from these it appears that the rate of heating or of 
cooling , of a mass of liquid acted on by the air at a higher or a lower 
temperature , is directly and simply proportional to the difference of tem¬ 
perature between the liquid and the air.* 

This is no more than a verification of the Newtonian law which is well 
known to be sensibly true only for very moderate differences, such as those 
observed by the committee which never exceeded 20°. The same law is 
also well known to fail entirely, when carried to very great differences. 
Assuming then the correctness of our result it enables us to determine, that 
while the iron in experiments on specific heats, was imparting its excess of 
heat to the water, the air gave to the liquid as much heat as it received from it , 
whenever the initial temperature of the water was twice as much below that 
of the room as the final temperature was above it. 

* This results from a mean of 14 comparisons between the differences of tempe¬ 
rature, and the corresponding times of heating through a given indefinitely small 
range of temperature, as one-tenth of a degree, by the formula D x : d x : : t : T. 
Where D and d are observed differences of temperature, between the water and 
the air, t and Tthe corresponding numbers of seconds required to raise the tempe¬ 
rature 0.1°; and x the power of the difference of temperature according to which 
the times vary. These fourteen comparisons give a mean value of x = 1.002. 


5 * 


/ 


56 


TABLE XV. 

Comparative table showing the rate of heating or of cooling of given li¬ 
quid masses in vessels of different sizes , by exposure in an atmosphere 
of known temperature. 






0> 


V 

1> 


0> 

_ 

as 






JS 


** 


13 

Pi 


<u 


• 

M 

p 

j 


% 

m 

go 

> 

iuo 

Cm 

o 

<p 

3 

Pi 

■M 

Cm 

O 

0) 

Cm 

O 

V 

3 

Cm 

O 

0) 

u* 

3 

■M 

0) 

M 

Cm 

O 

0) 

6j0 

M 

*M 

r+ 

3 

'P 

.S 

fcjO 

c 

P 0 ) 
p d CL> 

2 & 
Ph« 4 
c 

a 


V 

p- 

rt 

& 

<v 

DATE. 

• 

U 

c3 

* 

o 

c 

•m 

a 

. H 

a 

c 

o 

o 

<D 

Ph 

r* 

3 

■4-» 

3 

•*-> 

0> 

p* 

g 

ct 

3 

p* 

r*« 

3 

eS 

3 

P< 

g 

8 

o 

p 

J-l 

«s . 

-u 53 

<L> 

V) 

Ph 

c3 • 

■3.1 

a 

u 

Cm 

O 

-e 

^ o 
o 

pv 

2 Cm 

^ O 

Remarks. 

0 

6 


I 3 

'3 

o 

-d 

P 

•m 

# 

£ U 

M CS 

‘•M 
• M 

r* 

"d . 

.£ 33 

13 

.3 

s« 
s * 

& d 

s > 

'Ct V 
*3 

2 23 
p +> 

~ as 

2 ^ 

C3 

rP 


S2 



w 

£ 



CS 

C5 

O 

Ph 

O 



1835. 


thin 






// 

640. 


// 

128. 

Tliermom- 

1 

Jan. 10. 

20432 

glass 

cylin. 

69.7 

o 

63. 

69°2 

o 

63. 

6°45 

-°.5 

eter B.mer- 
curial == 43 

2 

•• 

20432 

wght 

69.8 

62.2 

69.4 

62.2 

7.4 

460. 

-°.4 

115. 

.7 grains of 




3325 









water. 

3 

Jan. 17. 

20432 

grs. 

41. 

61.5 

42. 

61.5 

20. 

435.5 

l.° 

43.55 


4 

•• 

20432 


42. 

61.5 

44. 

61.6 

18.55 

895. 

2. 

44.75 


5 

• • 

20432 


44. 

61.6 

46. 

61.8 

16.7 

945.5 

2. 

47.25 


6 

• • 

20432 


46. 

61.8 

48. 

61.8 

14.8 

1302. 

2. 

65.1 


7 

• • 

20432 


48. 

61.8 

50. 

61.6 

12.7 

1273.5 

2. 

63.675 


8 

• • 

20432 


50. 

61.6 

52. 

61.5 

10.55 

1534. 

2. 

76.7 


9 

• • 

20432 


52. 

61.5 

54. 

61.9 

8.7 

1912.5 

2. 

95.625 



1834. 











During this 

10 

Dec. 8. 

20274 


70.2 

74.5 

70.3 

74.5 

4.25 

37.5 

.1 

37.5 

and the 3 
following a 
brisk fire 

11 

• • 

20274 


70.4 

73. 

70.5 

73. 

3.55 

35. 

.1 

35. 

12 

• • 

20275 


70.75 

73. 

70.85 

73. 

2.20 

40. 

.1 

40. 

was kept up 
in the stove. 

13 

• • 

20275 


70.5 

73. 

71.6 

73. 

1.45 

45. 

.1 

40. 

14 

• • 

20275 


69.15 

73.5 

69.25 

73.5 

4.32 

25. 

.05 

50. 



1835. 


thin 









The largest 

15 

Mch,22. 

12676 

iron 

cylin. 

50.93 

64. 

51. 

64. 

13.03 

40. 

.07 

57. 

therm. (A) 
was used in 

16 

• • 

12676 

1733 

51. 

64. 

51.1 

64. 

12.95 

101. 

.1 

101. 

this & 4 fol- 

17 

• • 

12675 

grs. 

51.1 

64. 

51.2 

64. 

12.85 

125. 

.1 

125. 

lowing=196 
grs. water. 
Water ves- 

18 

• • 

12675 


51.2 

64. 

51.3 

64. 

12.75 

109. 

.1 

109. 

19 


12675 


51.3 

64. 

51.5 

64. 

12.6 

175. 

.2 

87.5 

sel in tin 
one,14 inch¬ 
es high. 




thin 









In this & 

20 

Feb, 21. 

16728 

glass 

jar 

2996 

55.975 

57. 

55.99 

57.3 

1.018 

103. 

.015 

687. 

9 following 
expts. the 
spirit the’*- 

21 


16728 

55.99 

57.3 

56.035 

57.6 

1.287 

63. 

.045 

140. 

22 


16728 

grs. 

56.035 

57.6 

56.05 

57.0 

1.557 

35. 

.015 

233. 

mometer C 

23 


16728 


50.05 

57.9 

56.06 

58.2 

1.845 

65. 

.01 

650. 

was used. 

24 


16728 


56.06 

58.2 

56.09 

58.5 

2.125 

172. 

.03 

573. 


25 


16728 


52.29 

58.5 

52.33 

58.5 

6.29 

126. 

.04 

315. 


26 


16728 


52.33 

58.5 

52.44 

58.5 

6.115 

72. 

.11 

65. 


27 


16728 


52.44 

58.5 

52.50 

58.5 

6.03 

60. 

.06 

100. 


28 


16728 


52.50 

58.5 

52.55 

58.5 

5.975 

107. 

.05 

214. 


29 


16728 


52.55 

58.5 

52.61 

58.5 

5.91 

68. 

.06 

213. 





thin 









Therm. B. 

30 

31 

Feb. 7. 

• • 

12676 

12676 

iron 

cylin. 

1733. 

59.7 

59.8 

68. 

68.25 

59.8 

59.9 

68.25 

68.25 

8.375 

8.40 

61. 

47. 

.1 

.1 

61. 

47. 

No enclos¬ 
ing tin cy¬ 
linder used. 





















































































57 


Strength of rolled copper. 

Tables numbered from XVI. to XXIII. inclusive present the results of ex¬ 
periments on the strength of boiler copper, both at ordinary and at elevated 
temperatures. From these tables it appears that at temperatures varying 
from 62 to 82 degrees Fah., the strength of rolled copper is by a mean ob¬ 
tained from 66 experiments on 8 different specimens within those limits, 
equal to 32826 pounds to the square inch. The irregularities of strength 
vary in the different specimens from 1-A. to 4 T 8 _ per cent, of the mean tena¬ 
city of the specimen in which they occur, and the mean value for the 8 bars 
is 3 t V per cent. The strips of copper as received from the manufacturers 
were of 4 different thicknesses, two of each thickness, and they were re¬ 
duced by filing to a nearly uniform size throughout their whole length. 
By an attentive observation, it will be seen that the thicker specimens give 
in general the higher results. 

Thus, No. 1, of which the original thickness was two-tenths of an inch, 
(called by the manufacturers three-sixteenths,) broke at eight trials, with an 
average force of 30704 lbs. per square inch. 

No. 2, with the same thickness, broke with 31468 lbs. as the average 
weight, at seven different trials. Hence the mean strength of these two 
bars is 31086 lbs. per square inch. 

Nos. 3 and 4, the thickness of which was a “ scant quarter ” of an inch, 
broke, the former at ten trials, with 33428 lbs., and the latter at six trials, 
with 33243 lbs., giving a mean of 33335. 

Nos. 6 and 7, having a thickness differing but little from the two pre¬ 
ceding, but rather greater, gave, the one at seven trials, 33411, and the 
other at nine, 33005 lbs. per square inch ; or, as a mean of the two speci¬ 
mens, 33205. 

Nos. 5 and 8, with a thickness before filing of not less than .27 of an inch, 
exhibited a tenacity of 33771 and 33780 lbs., the former being the mean of 
eleven and the latter of eight successive trials, showing a mean of 33775. 

The manufacturers have not, in their note accompanying the specimens, 
referred to any difference either in the kind of pig metal, the melting and 
refining which took place previous to rolling, or in any other circumstance 
attending the manufacture of the different bars, which could lead the com¬ 
mittee to assign a probable cause for the difference in point of cohesion be¬ 
tween the respective pairs. 

That difference between Nos. 5 and 8, and 1 and 2, is no less than 3071 
lbs. per square inch, or 9.3 per cent, of 32836, which we have found to be 
the average strength of eight specimens. 

But, as already stated, the irregularities observed in any one specimen, 
did not exceed 4— per cent, of its mean strength. It seems therefore pro¬ 
bable, that in reducing the lighter specimens to their final thickness, the 
operation was extended so far as to reduce below a proper point the tem¬ 
perature of the copper, and thus to injure its texture. It will be seen that 
the highest results obtained by the committee, are almost identical with that 
given by Mr. Rennie. 

In every calculation of the strength of materials for a steam boiler, the 
least strength known to be possessed by any part of the sheet, is that which 
alone can be relied on for fixing the pressure to which it may be subjected. 

For copper , at ordinary temperatures, the lowest result obtained by the 
committee was 30406 lbs. per sq. inch, and the mean minimum for the 8 bars 
32146 pounds. To other temperatures subsequent developements apply. 


58 


TABLE XVI. 


Experiments on copper bar No. 1, manufactured by John M' Kim, 
Jr., fy Sons of Baltimore, from South American pig, melted, refined 
and rolled into boiler-plate inch thick ;—cut off with the shears one 



Marks. 

Breadth. 

Thickness. 

Area of sections at the 

points measured before 

trial. 

No. of the Experiment. 

DATE. 

Area of the sections of 

fracture before trial. 

Temperature Fahren¬ 

heit. 

Breaking weight in the 

scale. 

Breaking weight X 

leverage. 

Friction. 

0 

.753 

.192 

.144576 


1833. 

sq. in. 

o 

lbs. 



1 

.751 

.189 

.141939 

1 

Nov. 7. 

.146412 

57.5 

159,5 

4785 

239. 

2 

.751 

.194 

.145694 








3 

.750 

.196 

.147000 








4 

.750 

.196 

.147000 








5 

.752 

.196 

.147392 








6 

.758 

.196 

.146608 

2 

« 

.146711 

120.? 

154. 

4620 

231. 

7 

.748 

.198 

.148104 








8 

.748 

.197 

.147356 








9 

.748 

.197 

.147356 








10 

.748 

.197 

.147356 








11 

.747 

.197 

.147159 

3 

tc 

.144836 

100.? 

156.5 

4695 

234.7 

12 

.747 

.196 

.146412 








13 

.746 

.195 

.145470 








14 

.745 

.196 

.146020 

4 

a 

.145015 

95.? 

154.5 

4635 

231.7 

15 

.745 

.195 

.145275 








16 

.743 

.197 

.146371 

5 

tt 

.147114 

90.? 

157. 

4710 

235.5 

17 

.743 

.198 

.147114 








18 

.746 

.195 

.145470 

6 

Nov, 9. 

.147000 

392. 

135. 

4050 

202.5 

19 

.744 

.195 

.145080 








20 

.743 

.195 

.144885 








21 

.743 

.195 

.144885 

7 

«< 

.143407 

75. 

153. 

4590 

229.5 

22 

.742 

.195 

.144690 








23 

.742 

.196 

.147392 








24 

.747 

.196 

.146412 

8 

Nov. 14. 

.147356 

392. 

135.125 

4054 

202.7 

25 

.747 

.196 

.146412 








26 

.743 

.197 

.146371 








27 

.742 

.196 

.147392 

9 

<( 

.147356 

68.75 

157.5 

4725 

236.2 

28 

.740 

.196 

.145040 








Mean of 29= 

.146146 

10 


.145705 

68.75 

159.75 

4792.5 

239.62 


Maximum .148104 









Minimum . 141939 

11 


.146706 

69. 

159. 

4770 

238.5 






Mean 






Mean of the 2 .145021 


of 11 = 

=.146147 





Diff. of the 2 .006165 









































59 


TABLE XVI. 

inch wide, filed to the size recorded , marked and gauged at every inch . 
Specific gravity 8.9866. 



z 

i 

X 

<L> 




• 

c/» 

fcX) 

rz 

0 

• 

QJ 


c 

*ci 

*+ 

3 

>H 

o 

> 

z 

z> 


w 

cn 

o 

O 

(/) 

0 

03 


QJ 

> 

• N 
♦- 

• • 

A 

c/j 

0 

ci 

C*- 

0 

REMARKS. 

o 

fc 

W 


w 

V) 

s 

■*-* 


5 « 

♦-» 73 

CO 3 

■ 5.2 
£ 2 

■*-» 

w 

0 

pH 



OB 

<V 

*-> 






112. 

None. 


The piece broken off had been 

4546. 

31049 

119. 

_i_ inch. 

3 0 . 

1 inch. 

No. 24^ 

elongated from 7 to 9.6 inches = 



141.5 


1 inch for every 2.69. 





Heated probably to the tempe¬ 
rature noted, by the machine 
which had been used in a hot ex- 


4389. 

29916 



“ 26j 

periment just before this trial, 
fracture took place in the piece 
stretched in the preceding expe- 






riment. 

4460.3 

30795 



“ 21i 

Fracture oblique across the 
thickness of the bar. 

4403.3 

30364 



“ 19| 

Same piece as above. 

4474.5 

30415 



“ 17 


3847.5 

26173 



“ 3J 

Part in hot oil from 2^ to 5j. 

4360.5 

30406 



“ 0£ 


3851.3 

26136 



“ 9 


4488.8 

30467 



“ 10 


4552.88 

31247 



“ 12£ 


4531.5 

30888 


/ 

“ 5§ 

The mean area of the 11 sec- 






tions of fractures is .000001 
square inch greater than the mean 
area of the 29 measured sections. 


















60 


TABLE XVII. 

Experiments on copper bar No. 2, manufactured by John M'Kim,jr., 1 
Sons, of Baltimore, from South American pig, melted, refined and y 
rolled into boiler plate three-sixteenths of an inch thick, cut off with the J 





0 ) 



O 

• p* 

OJ 

i 

O) 


Marks. 

Breadth. 

Thickness, 

Area of section hefc 
trial. 

DATE. 

No. of the Experimen 

Area of the section 

fracture before trial. 

Temperature Fahrenhf 

Breaking weight in 1 

scale. 

Breaking weight X 

verage. 

Friction. 

0 

.723 

.198 

.143154 








i 

.713 

.198 

.141174 








1 

.724 

.197 

.142628 

1833, 







1 * 

.735 

.197 

.144795 

Dec. 31, 

1 

.139895 

63.5 

153.5 

4605. 

230. 

2 

.720 

.196 

.141120 








n 

.721 

.194 

.139874 








3 

.742 

.199 

.147658 








3 * 

.745 

.200 

.149000 

1834. 
Jan. 4, 


* 





4 

4* 

.744 

.722 

.195 

.195 

.145080 

.140790 

2 

.145446 

32. 

159.75 

4792.5 

239. 

5 

.719 

.195 

.140205 








5* 

6 

.720 

.720 

.195 

.200 

.140400 

.144000 

U 

a 

O 

.143273 

32. 

160.25 

4807.5 

240. 

7 

.720 

.195 

.140400 








8 

9 

.724 

.728 

.198 

.199 

.143352 

.144872 

U 

4 

.140451 

32. 

159. 

4770. 

238.5 

10 

.732 

.197 

.144204 








11 

.732 

.197 

.144204 

« 

5 

.143023 

32. 

159. 

4770. 

238.5 

12 

13 

.736 

.739 

.200 

.198 

.147200 

.146322 

u 

6 

.140400 

32. 

159. 

4770. * 

238.5 

14 

.738 

.198 

•146124 

u 

7 

.142560 

32. 

159. 

4770. 

238.5 

15 

.737 

.198 

.145926 








16 

17 

.732 

.720 

.198 

.198 

.144936 

.142560 

u 

8 

.143352 

32. 

161. 

4830. 

241.5 

m 

18 

.713 

.713 

.197 

.196 

.140461 

.139748 

u 

9 

.145926 

32. 

161. 

4830. 

241.5 

19 

20 

.714 

.723 

.196 

.197 

.139944 

.142431 

Jan. 11. 

10 

.141424 

62.5 

158.25 

4747.5 

237. 

21 

.729 

.200 

.145800 








22 

.728 

.198 

.144144 








23 

.729 

.199 

.145071 








24 

.728 

.199 

.144872 








25 

.735 

.197 

.144795 


11 

.144872 

62.5 

159.5 

4777.5 

238. 

26 

.737 

.200 

.147400 








27 

.730 

.199 

.145270 

u 

12 

.144872 

62.5 

160. 

4800. 

240. 






Mean of 35 

= .143711 

u 

13 

.146868 

62.5 

163.25 

4897.5 

244. 


Maximum .149000 

u 

14 

.145702 

62.5 

160.25 

4807.5 

240. 


Minimum .139748 

u 

15 

.146075 

62.5 

160.25 

4807.5 

240. 

Mean of the 2 

= .144374 


Mean of 14 = 

.143519 





Diff. of the 2 

=.009252 













































61 


TABLE XVII. 

f shears one inch wide , filed to the size recorded , marked and gauged 
•j at every inch , and in some parts to every half inch, Specific gravity 
8.9866. 


Effective strain. 

Strength in pounds per 
square inch. 

Temp, of the room. 

Weight producing elon¬ 

gation before fracture. 

Elongation observed. 

Point of fracture. 




lbs. 







ai2. 

1st permanent - '] 







126. 

.35 inch 


No. 

4375. 

31273 



133. 

1.12 “ 


18f 




< 

140. 

2.00 « 

> 






143.5 

2.50 “ 







147. 

3.10 “ 







Il53.5 

Broke. 



4553.5 

31307 

59.°5 



25| 

4567.5 

31870 

59. 



20! 

4531.5 

32264 

59. 



m 

4531.5 

31684 

59. 



0 ! 

4531.5 

32272 

59. 



5! 

4531.5 

31787 

59. 



17 

4588.5 

32007 

59. 



8 

4588.5 

31444 

59. 



15 

4510.5 

31893 




4f 

4539.5 

1 

31334 




24 

4560. 

31476 




24 

4653.5 

31685 




26! 

4567.5 

31348 




11! 

4567.5 

31268 




14! 


REMARKS. 


The filing of this bar being 
less accurate than of others it 
was gauged in part at half inch 
distances. The space between 
the wedges, and on which the 
elongations were measured, was 
25 inches. 

Part in ice from 22 to 25. 
Broke just without the ice. 

The part fractured must have 
been between 59° and 32°—same 
part in ice as above. 

Part in ice from 8 to 11 inclu¬ 
sive. 

Part in ice from 11 to 14 in¬ 
clusive. 

Do. 

Broke near the end. 

Part in ice from 10 to 13 inclu¬ 
sive. 

Broke outside of the ice. No 
fracture has taken place in ice. 

The following experiments 
were made on the 


remaining 


the room, not being long enough 
for trial in ice. 

Reduced but not broken at 24* 
When it appeared about to breaks 
lbs. were taken oft' to prevent 
nediate fracture. One pound 


The mean area of the 14 sec¬ 
tions of fracture is .000192 sq. 
inch less than the mean area of 
the 35 measured sections. 





























6.2 


TABLE XVIII. 


Experiments on copper bar No. 3., manufactured by John M*Kim, 
Jr., fy Sons, of Baltimore, from South American pig, melted, refined 
and rolled into boiler plate, scant | of an inch thick ; cut off with the 


} 


5/5 

X 

u 

a 

s 

Breadth. 

Thickness. 

Area of section before 
trial. 

DATE. 

I No. of experiment. 

Area of the section of 

fracture before trial. 

Temperature Fahren¬ 

heit. 

Breaking weight in the 

scale. 

0 

.708 

.245 

.173460 

1833. 

1 

.164000 

65.5 

193.75 

l 

.708 

.245 

.173460 

Dec, 8. 





2 

.700 

.245 

.171500 


l 




3 

.695 

.244 

.169580 

a 

2 

.166970 

65.5 

194.75 

4 

.686 

.246 

.168756 






5 

.678 

.241 

.163398 






6 

.688 

.241 

.165808 

u 

3 

.169031 

65.5 

195.25 

7 

.690 

.243 

.167670 






8 

.695 

.245 

.170275 






9 

.700 

.244 

.170800 

a 

4 

.171260 

65.25 

195.25 

10 

.700 

.245 

.171500 






11 

.700 

.240 

.168000 






12 

.700 

.243 

.170100 

u 

5 

.173460 

66. 

196.5 

13 

.710 

.240 

.170400 






14 

.710 

.242 

.170820 






15 

.710 

.246 

.174660 

it 

6 

.168000 

122. 

194.25 

16 

.712 

.243 

.173016 






17 

,712 

.244 

.173728 






18 

.712 

.243 

.173016 

Dec. 15. 

7 

.170800 

56. 

195. 

19 

.711 

.242 

.172062 






20 

.712 

.243 

.173016 






21 

.712 

.241 

.175992 






22 

.713 

.245 

.174685 

6 t 

8 

.165808 

56. 

195.25 

23 

.713 

.244 

.173972 






24 

.713 

.243 

.173259 






25 

.713 

.240 

.171120 

li 

9 

.170760 

124. 

201.75 

26 

.711 

.240 

.170640 






27 

,708 

.238 

.168504 










Dec. 22. 

10 

.173700 

124. 

198.75 


Mean of 28 = 

.171028 







Maximum 

.174685 

it 

12 

.172062 

126. 

199.75 


Minimum 

.163398 






Mean of the two 

.169041 

a 

11 

.172541 

61.5 

201.25 

DifF. of the two 

.011287 










ii 

13 

.173259 

61.5 

200. 





a 

14 

.173372 

61.5 

198.75 






Mean of 14 = 

.170358 



































63 


TABLE XVIII. 

shears one inch wide, filed to the size recorded, marked and gauged at 
every inch. Specific gravity 8.7891. 


Breaking weight X le¬ 

verage. 

Friction. 

Effective strain. 

[ 

Strength in pounds per 

square inch. 

Point of fracture. 

REMARKS. 

5812.5 

290.6 

5521.9 

33670 

No, 5i 


5842.5 

292.61 

5550,4 

33242 

“ 4* 


5857.5 

292.8 

5564.7 

32921 

“ 3£ 


5857.5 

292.8 

5564.7 

32494 

“ 21 

1 

5895 

294.7 

5600.3 

32286 

“ 0J 


5827.5 

291.3 

5536.2 

32949 

“ 11 

Nos. 11,12 and 13 in oil bath, 

A part which had been griped 

5750 

292.5 

5557.5 

32538 

“ 9 

by the wedges remained unbrok¬ 
en, betraying no unusual weak¬ 
ness. 

Broken where it had been 

5857.5 

292.87 

5564.8 

33561 

“ 6 

griped before. 

6052.5 

302.6 

5749.9 

33672 

“ 25| 

Broke in oil. 

Broke just outside of the oil 

5962.5 

298.1 

5664.4 

32610 

“ 14f 

bath—part included being from 
15 to 18. 

5992.5 

299.6 

5692.9 

33086 

“ 19 

Broke in the oil. 

6037.5 

301.8 

5735.7 

33242 

“ m 


6000 

300 

5700 

32899 

“ 24 

• 

5962.5 

298.1 

5664.4 

32672 

“ 17£ 

Torn off by the wedges. 

The mean area of the 14 sec¬ 
tions of fracture .000670 square 
inch less than the mean area of 
the 28 sections measured. 


6 


















64 


TABLE XIX. 

Experiments on copper bar No. 4. Manufactured by John M ’ Kim, 
Jr., and Sons of Baltimore, from South American pig, melted, refined 
and rolled into boiler plate, scant | of an inch thick, cut off with the 


Marks. 

Breadth. 

Thickness. 

Area of section before 
trial. 

Elastic, tried before 

1st frac. 

DATE. 

No. of the experiment. 

Area of the section of 

fracture before trial. 

Temperature Fahren¬ 

heit. 1 

Weight producing 
elongation. 

Total recoil. 

Elasticity of the 

machine. 

Elasticity of the bar.j 

0 

.717 

.240 

.172080 

r ioi 

10 







1 

.717 

.240 

.172080 


171 

20 







2 

.717 

.240 

.172080 


241 

30 



1 OO A 




3 

.717 

.237 

.169929 


311 

381 



i. OOti 



o 

4 

.715 

.237 

.169455 


381 

A 

44 



May 10. 

i 

.169455 

692 

5 

.715 

.237 

.169455 


45i 

52 







6 

.711 

.237 

.168507 


52l 

57 







/ 

.718 

.237 

.170166 


56 

591 







8 

.721 

.237 

.170877 


63 

68 







9 

.725 

.237 

.171825 


70 

73 



u 

2 

.171914 

844 

10 

.728 

.237 

.172536 


77 

79 







11 

.729 

.237 

.172773 

CO 

84 

871 







12 

.732 

.237 

.173484 

GO 

T—( 

91 

93 



May 17. 

3 

.175311 

1016 

13 

.732 

.237 

.173484 


98 

97 







14 

.732 

.237 

.173484 

CO 

105 

102 







15 

.732 

.237 

.173484 

cd 

112 

104 



tt 

4 

.178147 

1032 

16 

.733 

.240 

.175920 


119 

114 







17 

.735 

.240 

.176400 


126 

117 







18 

.738 

.240 

.177120 


133 

125 



May 24. 

5 

.179700 

81.5 

19 

.740 

.240 

.177600 


140 

132 







20 

.740 

.238 

.176120 


143.5 

128.5 







21 

.740 

.238 

.176120 


147 

129 



u 

6 

.178560 

81.5 

22 

.742 

.241 

.178822 


154 

133 







23 

.743 

.240 

.178320 


1571 

144 







24 

.748 

.240 

.179520 


161 

137 



u 

7 

.176160 

81.5 

25 

.749 

.240 

.179760 


1641 

152 







26 

.744 

.240 

.178560 


1164£ 

1471 

1001 

47' 

it 

8 

.176490 

81.5 

27 

.744 

.240 

.178560 

The last of the above 









observations was made 






Mean of 28 = 

=.174233 

w r hen the bar had been un- 

it 

9 

.172358 

81. 





der strain 

one week, after 






Maximum . 179760 

which the extension in 27 

ti 

10 

.173484 

81. 


Minimum 

.168507 

inches had become of 









an 

inch. 


10 0 

u 

11 

.173484 

81. 

Mean of the two = 

= .174133 

The elasticity 

w T as 

now 









taken several times, 

the 

May 31. 

12 

.168981 

69.5 


Dm. of the two .011253 

mean being 147j. 

The 









elasticity 

of the machine 









under the 

same weight, 

u 

13 

.168922 

69.5 





was found to 

cr 

CD 

S' 

o 









hence that of the copper 

it 

14 

.172080 

69.5 





bar was 47'. 











1 





Mn. of 14 


' .173932 
















































65 


TABLE XIX. 

f shears one inch wide , filed to the size recorded , marked and gauged at 
< every inch. Specific gravity 8.7388. 


Breaking weight in 
the scale. 

Breaking weight X 
leverage. 

Friction. 

Effective strain. 

Strength in pounds per 
square inch. 

Point of fracture. 

t 

REMARKS. 

130.5 

3915. 

195.7' 

3719.3 

21948 

No. 4. 

The elasticities of the machine 
having been taken more than two 
years before these experiments 
were made, were found to have 
varied so much as to render use¬ 
less any attempt to decide, from 
the trials now made, the succes¬ 
sive elasticities of the bar. 

101.5 

3045, 

152,2 

2882.8 

16768 

“ 0s 


68. 

2040. 

102. 

1938. 

11054 

“ 15J 


68. 

2040. 

102, 

1938. 

10878 

“ 212 


•200.5 

6015. 

300.75 

5714.25 

31798 

“ 242 

This part had been heated in 
a former trial. 

203.25 

6097.5 

304.88 

5792.62 

32440 

“ 26J 


200. 

6000. 

300. 

5700. 

32357 

“ 1 6k 

Heated at this section in ex¬ 
periment 3d. 

200. 

6000. 

300. 

5700. 

32296 

“ 192 

Heated in experiment 4th. 

201. 

6030. 

301.5 

5728.5 

33236 

“ 92 

Heated in experiment 2d. 

201.25 

6037.5 

301.87 

5735.63 

33061 

“ 131 


201.75 

6052.5 

302.62 

5749.88 

33143 

“ 12 


196.25 

5887.5 

294.37 

5593.13 

33099 

“ 


198.5 

5955. 

297.75 

5657.25 

33490 

“ 62 


198.25 

5947.5 

297.37 

5650.13 

32834 

“ 1 

The mean area of the 14 sec¬ 
tions of fracture .000301 square 
inch less than the mean area of 
the 28 measured sections. 




















66 


TABLE XX. 

Experiments on copper bar No. 5. Manufactured by John M' Kim, Jr., 
fy Sons, of Baltimore, from South American pig , melted , refined, and 
rolled into boiler plate full | inc/i ^AicA, wi/A the shears 1 incA 





U 




ft 

O 





<2 


£ 

0) 


S3 

J, 




.a 


c 


£ 

Ph 






53 


o •£ 





.2 


ft 

x 



CJ 



• 

1/5 

CZ> 

V 

c0 


a> 

0 ) 

DATE. 


3 

•M 

C/5 

.M 

• 

<— 

■3 

a 

d 

a 

o 

cl 

<L> 


ft 

O 


° 9> 

s 1 

I* 

0) 

ft 

s 

S 

u 

h 

Ai 

trial. 


& 


< £ 

h 

0 

.778 

.260 

.202280 


• 




1 

.774 

.264 

.204336 



1834. 



2 

.764 

.265 

.202460 


1 

Jan. 25. 

.202407 

472 

3 

.766 

.263 

.201458 






4 

.768 

.264 

.202752 






5 

.767 

.267 

.204789 


2 

Feb. 1. 

.205279 

472 

6 

.767 

.267 

.204789 






7 

.767 

.269 

.206323 


3 

<( 

.201585 

80 

8 

.767 

.267 

.204789 





ap. 

9 

.768 

.267 

.205056 


4 

cc 

.204229 

64 

10 

.770 

.267 

.205590 






11 

.770 

.267 

.205590 


5 

66 

.203846 

64 

12 

.771 

.267 

,205857 






13 

.771 

.266 

.205086 


6 

u 

.203023 

64 

14 

.770 

.263 

.202510 






15 

.770 

.265 

.204050 






16 

.773 

.260 

.200980 


7 

<( 

.203036 

64 

17 

.772 

.263 

.203036 






18 

.772 

.263 

.203036 






19 

.772 

.264 

.203808 


8 

il 

.206092 

64 

20 

.772 

.268 

.206896 






21 

.768 

.268 

.205824 


9 

Feb. 8. 

.204280 

482 

22 

.761 

.267 

.203187 






23 

.758 

.266 

.201628 


10 

u 

.202210 

60 

24 

.755 

.267 

.201585 






25 

.767 

.265 

.203255 


11 

(l 

.202929 

60 

26 

.769 

.266 

.204554 






27 

.770 

.267 

| .205590 


12 

u 

.204789 

60 


Mean of 28= 

.203967 


13 

il 

.205790 

60 


Maximum .206323 
Minimum .200980 

| .005343 differ. 

14 

a 

.204789 

60 


Mean of the 2 

=.203651 


M 

ean of 14= 

=.203877 


































67 


TABLE XX. 

'wide, filed to the dimensions recorded , marked and gauged at every 
* inch . Specific gravity 8.7857. 














QJ 

a- 




■w 

.£P 

O 

6j0 

a 

o j 
> 


) - 

.s 

*8 

CO 

£ 


3 

O 


£ 

ip 

X 

£ 

w 

> 



Cm 

Cm 

REMARKS. 

13 

■M 

O 

%-> 

o 

fcjo £ 

r» . m 


O 

£ 

o 

Pn 


Brci 

scale. 

M 

o 

• JH 

ttt 

w 

w g 

a 4 

CO 










f Part in oil from 20° to 24°. 

| The thermometer was noted at 

192. 

5760. 

288. 

5472. 

27034 

No. 224 

d the time 482, but on being re- 

195.75 






12| 

| graduated was found 10 de- 
Lgrees too high at this point. 

5872.5 

293.6 

5578.9 

27128 

U 


238.5 

7155. 

357.75 

6797.25 

33719 

tc 

24 


246.25 

7387.5 

369.87 

7017.63 

34361 

(C 

25^ 


241.25 

7237.5 

i 

361.87 

6875.63 

33729 

u 

21f 


240.5 

7215. 

360.75 

6854.25 

33761 


144 





6889.88 

33932 


17| 

^ Fracture remote from the 

241.75 

7252.5 

362.62 

u 

£ wedges. 

242.75 

7282.5 

364.17 

6918.33 

33569 

u 

20| 


191.75 

5752.5 

287.62 

5464.88 

26752 

a 

43 


240.75 

7222.5 

361.12 

6861.38 

33931 

u 

24 


240.75 

7222.5 

361.12 

6861.38 

33812 

(< 

14 


241. 

7230. 

361.50 

6869.5 

33544 

64 

5 


241.75 

7252.5 

362.62 

6889.88 

33480 

u 

114 

T Sooner parted than the pre- 

241.75 

7252.5 

362.62 

6889.88 

33644 

u 

8 

< ceding. Weight may have 
Cbeen a trifle too great. 



# 





The mean area of the 14 sec- 








tions of fracture .000090 square 
inch less than the mean area of 
the 28 measured sections. 


6 * 


















68 


TABLE XXI. 

Experiments on copper bar No. 6. Manufactured by John M'Kim, 
Jr., and Sons, of Baltimore, from South American pig, melted, refined 
and rolled into boiler plate, full | of an inch thick, cut off with the 





d) 

U 


i 

Cm 

O 

a 

d 



- ■ 

<2 

<u 


d> 

Pi 

x 


<U 

a: 

•M 



(A 

a 


w 

M ,2 


■M 

(/) 

At 

£ 

QJ 

P 

O 


Cm 

O 

O 

0) ^ 

D 

ap 

’C 

u 

a 

*m 

A 

cl 

<D 

M 

o 

'.H 

h 

8 

Cfl 

Cm 

O 

ct 

DATE. 

<5 

£ 

■3 <3 
.0 
° U 

CS '-1 

•M 

Pi 

£ 

£ 

to 




d 

j_, • 

"3 


3 • 

<U 

aj a 

< § 

5 • 

Si 




■M 


£ 

* 

ja 

K o 

W 

0 

.737 

.253 

.186461 

1834. 
Feb. 15. 





1 

2 

.737 

.736 

.253 

.253 

.186461 

.186208 

1 

.186113 

545 

166. 

3 

4 

.736 

.733 

.253 

.253 

.186208 

.185449 

<( 

2 

.186271 

70 

213.5 

5 

.733 

.253 

.185449 






6 

.733 

.253 

.185449 

a 

3 

.186461 

66 

215.25 

7 

.733 

.253 

.185449 






8 

.733 

.253 

.185449 






9 

.733 

.253 

.185449 

Feb. 22. 

4 

,186043 

561 

163.5 

10 

.736 

.253 

.186208 






11 

.736 

.253 

.186208 






12 

.736 

.253 

.186208 


5 

.185449 

71 

210.5 

13 

.736 

.253 

.186208 






14 

.735 

.253 

.185955 

u 

6 

.185449 

71 

210.5 

15 

.735 

.253 

.185955 






16 

.735 

.253 

.185955 

(t 

7 

.186208 

70 

214.5 

17 

.735 

.253 

.185955 






18 

.735 

.253 

.185955 






19 

.735 

.253 

.185955 

(( 

8 

.185955 

801 

123. 

20 

.735 

.253 

.185955 





21 

.735 

.253 

.185955 






22 

.735 

.253 

.185955 

March 1. 

9 

.185955 

62 

216.75 

23 

.735 

.253 

.185955 





24 

.735 

.253 

.185955 

u 

10 

.185955 

61 

218.25 

25 

.736 

.253 

.186208 





26 

.736 

.253 

.186208 

<( 

11 

.185955 

60 

219.75 

27 

.736 

.253 

.186208 

u 

12 

.186208 

59 

219.75 







Mean of 28 = 

= .185964 






Maximum . 186461 
Minimum .185449 

u 

13 

.186208 

58 

220. 

Mean of the 2 = 

= .186455 

March 8. 

14 

.185955 

70 

218, 

Differ, of the 2 = 

=.001012 


Mean of 14 = 

J .186013 




































69 


TABLE XXI. 

shears one inch wide, filed to the dimensions recorded, marked and 
gauged at every inch. Specific gravity 8.9666. 


Jj 



QJ 



X 

■M 


• 

.2 

C/) 

*73 

S3 

Q? 

3 


bp 

• 

c 


a 

p- 

o 


£ 

to 

o 

*c 

> 

• M 
•M 

a . 

Z — 

& 

Cm 

O 

REMARKS. 

« 

■g 

£ i? 


o 

ee 

H 

to.S 

S g 

-m c3 

■*-> 

r* 

• M 

o 

Ph 


pq 2 

D 

> 






4980 

249. 

4731. 

25420 

No. 3| 

Broke in tin; part immersed 
(from 2 to 6 inclusive.) 

6405 

320. 

6085. 

32666 

“ If 


6457.5 

322.8 

6134.6 

32900 

“ 0 


4905 

245.2 

4659.8 

25047 

“ 9f 

0 

Broke in tin; part immersed 
from 8 to 11£. 

6315 

315.7 

5999.2 

32350 

“ 8 

Embraced in the preceding 
hot portion. 

6315 

315.7 

5999.2 

32350 

“ H 

Had been heated. 

6435 

321.7 

6113.25 

32830 

“ 27 

Not tried before. 

3690 

184. 

3506. 

18854 

“ 18J 

Very little extended before 
fracture. 

6502 

325. 

6177. 

33218 

“ 20 

A portion formerly gripped by 
the wedges, is embraced within 

6547 

327. 

6220. 

33443 

“ 2H 

this part of the bar, but does not 
give way, proving that the action 

6592 

329. 

6263. 

33682 

“ 23 

of the machine on such parts does 
not weaken the material. 

6592 

329. 

6263. 

33634 

“ 25^ 

Fracture at a place formerly 
heated. 

6600 

330. 

6270. 

33672 

“ 13 


6540 

327. 

6213. 

33401 

“ m 

The mean area of the 14 sec- 






tions of fracture .000049 great¬ 
er than the mean area of the 28 






measured sections. 






















70 


TABLE XXII. 

Experiments on copper bar No. 7. Manufactured by John M*Kim, 
Jr., and Sons, of Baltimore, from South American pig, melted, refined 
and rolled into boiler plate, full \ of an inch thick. Cut off with the 


Marks. 

Breadth. 

Thickness. 

Area of sections at the 
points measured before 
fracture. 


No. of Experiment. 

DATE. 

Area of the section of 

fracture before trial. 

Temperature Fahren¬ 

heit. 

Breaking weight in the 

scale. 

0 

.743 

.248 

.184264 



1834. 




1 

.743 

.246 

.182778 


1 

Apl. 19. 

.185007 

912 

96 

2 

.744 

.248 

.184512 







3 

.744 

.248 

.184512 







4 

.744 

.249 

.185256 


2 

it 

,184884 

90 

215 

5 

.743 

.249 

.185007 





ap. 


6 

.743 

.249 

.185007 







7 

.743 

.249 

.185007 


3 

tt 

.184016 

602 

144 

8 

.742 

.249 

.184758 







9 

.742 

.249 

.184758 







10 

.742 

.248 

.184016 


4 

tt 

.184016 

817 

108 

11 

.742 

.248 

.184016 







12 

.742 

.248 

.184016 







13 

.742 

.248 

.184016 


5 

Apl. 26. 

.184007 

63 

214 

14 

.742 

.248 

.184016 







12 

.742 

.248 

.184016 







16 

.742 

.248 

.184016 







17 

.742 

.248 

.184016 


6 

44 

.184512 

63 

217 

18 

.742 

.249 

.184758 







19 

.742 

.249 

.184758 







20 

.742 

.249 

.184758 







21 

.743 

.249 

.185007 


7 

tt 

.184007 

992 

72 

22 

.743 

.249 

.185007 







23 

.743 

.249 

.185007 







24 

.743 

.248 

.184264 







25 

.743 

.248 

.184264 







26 

.743 

.248 

.184264 


8 

May. 24, 

.184264 

81.75 

212 

27 

.740 

.248 

.183520 







28 

.743 

.248 

.184264 












9 

44 

.183892 

81.75 

216.75 


Mean of 29 = 

.184402 








Maximum 

.185256 


10 

tt 

.184882 

S1.75 

213.25 


Minimum 

.182778 

> .002478 Diff. 











11 

44 

.184758 

81.75 

213.25 


Mean of the 2 

.184017 | 












12 

4 4 

.184016 

81.75 

213.75 





13 

tt 

.184016 

81.5 

214.5 





Mean of 13 = 

.184329 
































71 

TABLE XXII. 

shears one inch ivide, filed to the size recorded , marked and gauged at 
every inch. Specific gravity , 8.8543. 


Breaking; weight X le¬ 
verage. 

, 

Friction. 

Effective strain. 

Strength in pounds per 
square inch. 

Point of fracture. 

2880 

144 

2736 

14789 

No. 5* 

6450 

322 

6128 

33145 

“ H 

4320 

216 

4104 

22302 

“ m 

3240 

162 

3078 

16727 

“ 17 

6420 

321 

6099 

/ 

32966 

“ 8 

6510 

325.5 

6184 

33515 

“ 3 

2160 

108 

2052 

11091 

“ 23 

6360 

318 

6042 

32790 

“ 24$ 

6502.5 

325,12 

6177.38 

33592 

“ 27£ 

6397.5 

319.87 

6077.63 

32819 

“ 20$ 

6397.5 

319.87 

6077.63 

32895 

“ 18$ 

6412.5 

320.62 

6091.88 

33105 

“ m 

6435 

321.75 

6113.25 

33221 

“ 15 


REMARKS. 


Part in tin from 3 to 6J. 


f Part in metal 9 to 12 inclusive. 

| The temperature recorded issup- 
-<( posed to be a little too low, as a 
| short time elapsed after the frac- 
l_ture, before it was noted. 


Part in metal from 22 to 24^. 
As the surface of the copper was 
j not oxidated before trial, this 
) temperature caused some alloy- 
I ing which may have slightly di- 
Lminished the strength. 

Probably a little weakened by 
the preceding high temperature. 




The mean area of the 13 sec¬ 
tions of fracture .000073 square 
inch less than the mean area of 
the 29 measured sections. 













72- 


TABLE XXIII. 


Experiments on copper bar No. 8. Manufactured by John M' Kim, 
Jr., 4* Sons, of Baltimore, from South American pig, melted, refined, ► 
and rolled into boiler plate, full | inch thick. Cut off with the shears w 





sections 
i trial. 


■*■3 

0 

<D 

g 

0> 


Cm 

C 

jj-3 
«-> .2 

•d 

a 

Breaking weight in the 

scale. 

Marks. 

Breadth. 

Thickness. 

Area of the 
measured before 


X 

<v 

<M 

o 

o 

DATE. 

|<2 

CJ 

<4- ^ 

c o 
ci i 
u +* 

C3 

Cm 

<Lt 

Sh 

s 

■m 

§j 

£ 

H 

0 

.766 

.256 

.196096 



1833. 




1 

.766 

.262 

.200692 


l 

Nov. 16. 

.202510 

212° 

225.75 

2 

.766 

.260 

.199160 







3 

.768 

.260 

.199680 







4 

.769 

.263 

.202247 


2 

it 

.201391 

65.75 

233. 

5 

.770 

.263 

.202510 







6 

.767 

.263 

.201721 







7 

.768 

.256 

.196608 


3 

<< 

.199290 

65.75 

233. 

8 

.764 

.263 

.200932 







9 

.766 

.255 

.195330 


4 

Nov. 21. 

.197597 

212. 

226. 

10 

.766 

.254 

.194564 







11 

.768 

.257 

.197376 


5 

a 

.197284 

302. 

215. 

12 

.766 

.258 

.197628 







13 

.766 

.259 

.198394 


6 

tt 

.199034 

62. 

229. 

14 

.768 

.259 

.198912 







15 

.768 

.259 

.198912 







16 

.769 

.263 

.202247 


7 

tt 

.197197 

62. 

233,5 

17 

.772 

.260 

.200720 







18 

.772 

.260 

.200720 







19 

.772 

.260 

.200720 


8 

tt 

.201721 

64. 

235.25 

19$ 

.770 

.260 

.200200 







20 

.759 

.258 

.195822 


9 

tt 

.197502 

60. 

238. 

20^ 

.751 

.258 

.193758 







21 

.755 

.257 

.194035 







22 

.762 

.258 

.196596 


10 

Nov. 23. 

.194569 

60. 

238. 

23 

.765 

.258 

.197370 







24 

.764 

.258 

.197112 







25 

.765 

.261 

.199665 


11 

a 

.202247 

302. 

217.75 

26 

.761 

.262 

.199382 







27 

.762 

.258 

.196586 


12 

a 

.200720 

65. 

235.75 

28 

.7571.258 

.195306 







Mean of 31= 

=. 198420 


13 

a 

.198912 

65. 

235,75 

Maximum 

Minimum 

.202510 

.193758 

j .008752 Diff. 

14 

a 

.197525 

65. 

232. 


Mean of the 2=.198134j Mean of 14=.199107 
























73 


TABLE XXIII. 


f 1 inch wide , filed to the dimensions recorded , marked and gauged at 
< every inch. Specific gravity 8.9285. 


bo 



u 

<D 

Ph 

6 


u 

Zi 



3 

+~> 


> 

Z) 



d 

o 

cS 

REMARKS. 

X 

p 

• 

N 

a 

Friction. 

o 

> 

& 

W 

Strength 
square inch 

o 

•M 

.s 

*3 

Ch 


6772.5 

338.6 

6433.9 

31778 

No. 5 

Part in oil from 2| to 5|. 

6990. 

349.5 

6640.5 

32973 

“ 3§ 

C May have been warmed by 
£ the machine. 

6990. 

349.5 

6640.5 

33321 

“ 2i 


6780. 

339. 

6441. 

32596 

“ Ilf 

Part in oil from 11 to 14^. 

6450. 

• 

322.5 

6127.5 

31059 

“ 23§ 

Part in oil from 22 to 25. 

6870. 

343.5 

6526.5 

32791 

“ 26f 

C Probably somewhat heated 
£ by the machine. 






C The fractured part had been 

7005. 

350.25 

6654.75 

33749 

8| 

J gripped in a former experiment, 
^1 but showed no weakening from 






l^that cause. 

7057.5 

352.87 

6704.63 

33237 

6 


7140. 

357. 

6783. 

34343 

“ 111 

C Broke with the same w’eight 

7140. 

357. 

6783. 

34862 

“ 10 

< as the preceding, but with a 
L slow motion. 

6532.5 

326.62 

6205.88 

30685 

“ 16 

Part in oil from 15| to 18|. 

7072.5 

353.62 

6718.88 

33474 

“ 17 


7072.5 

353.62 

6718.88 

33783 

“ 14 

C Broke rapidly—weight ap- 
£ peared to be a little too great. 

6960. 

348. 

1 

) 

6612. 

33474 

“ 2 6 § 

The mean area of the 14 sec¬ 
tions of fracture .000701 square 
inch greater than the mean area 
of the 31 sections measured. 
























74 


Effect of increased temperature on copper. 

The effect of temperature on tenacity, has been hitherto but slightly ex¬ 
amined, either for theoretical or practical purposes. The general truth that 
heat diminishes, and eventually overcomes cohesion, is too well established 
by daily observation to admit of question. 

The temperature of no tenacity , is generally supposed to be that at which 
the fusing point of the given substance is placed, and the point of maximum 
tenacity ought, upon general principles, to be found at the point where 
least heat prevails, that is, at the natural zero, or point of absolute cold , if 
such a point exist in nature. Between these two extremes, it might be 
supposed that the tenacities of different substances, particularly such as are 
capable of passing immediately from the solid to the liquid state, would be 
found to obey certain laws. As the total cohesion at the maximum would 
present to a mechanical agent tending to overcome it, the whole of its re¬ 
sistance, and as, at more elevated temperatures, a part of that tenacity would 
be overcome by heat, and the rest must be destroyed by the mechanical 
force, it is evidently a question of experiment, to decide what relation the 
two forces have to each other at the several temperatures between the two 
extremes to which we have just alluded. To decide the theoretical question, 
or, in other words, to deduce, from the experiments, a law which might be 
expressed in an abstract form corresponding to all the possible phenomena, 
would require a state of the materials different from that usually found in 
commerce or employed in the arts. It would also, as we have seen, require 
a knowledge of that, about which philosophers no less than practical men, 
are far from being agreed;—namely, the point of absolute cold. As the 
purposes of this committee did not lead them to investigate the problem in 
all its possible bearings, but only in view of the limits which practice as¬ 
signs, and with the conditions commonly given to the materials, it will not 
perhaps, be easy, to construct from the tables a formula in all respects un¬ 
exceptionable. 

The general course of experiments involved the necessity of operating, 
at the different temperatures, on different bars of copper, and as all the bars 
are not found to give, even at ordinary temperatures, the same strength, for 
equal areas of section, it became necessary to deduce from experiments on 
each bar, at some assumed low temperature, a standard tenacity with which 
to compare its strength at every other point. The part of this standard 
tenacity which was taken away by the heat at the higher temperatures, be¬ 
coming known by the experiment, a comparison was furnished for deciding 
approximately the relation between the temperature given, and the portion 
of tenacity which it had overcome. It will be found on an inspection of 
Table XXIV. containing the comparison of these experiments, that on the 
eight different bars, the whole number of trials which furnished standards of 
comparison, at ordinary temperatures, was sixty-six, and consequently on 
an average about eight trials to each bar; while at the elevated temperatures 
there were made thirty-nine different experiments at nineteen different 
points on the scale, the greater number of points, however, having but one 
experiment each. 

An inspection of plate IX., where these experiments are represented, will 
show that at nearly all parts of the scale, within which the trials were made, 
the strength diminishes more rapidly than the temperature increases, but 
some of the higher experiments indicate that the conditions of the law are 
such as to be represented by a curve, having a point of inflection. It will 


75 


also be observed that the three experiments which appear anomalous, and 
which in the plate are marked with queries, are all found in trials of the 
same bar of copper, (No. 7,) and that all these might be referred to a curve, 
varying but little in form from that which we have traced. It is not how¬ 
ever necessary to suppose that these experiments belong to a different curve, 
for upon recurring to the table of bar No. 7. (Table XXII.) it will be found 
that one of the anomalies is satisfactorily accounted for by a delay in taking 
the temperature after the fracture had occurred, and that one of the others 
and probably both, were cases of weakening by a slight alloying of the 
copper by the melted metal through which it passed, in consequence of not 
having been defended by oxide. The other bars tried at high temperatures 
were treated with dilute nitric acid, creating a thin film of oxide, which 
effectually defended the surface, without sensibly diminishing even the 
smoothness of the bar. 

It will be observed that the difference of tenacity, at the lower tempera¬ 
tures, for a difference of from 60 to 90 degrees, is scarcely greater than the 
actual irregularities of structure in the metal at common temperatures, and 
consequently, it was not practicable from these experiments alone to deduce 
a law which should express the tenacities at all points between the maxi¬ 
mum above referred to, and the melting point of the metal. Nor would 
much confidence probably have been reposed in results thus obtained. 

In laying down the results in plate IX., the line a b is made to represent 
the total tenacity of copper at 32°. The horizontal dotted lines express the 
observed temperatures above 32°, and the vertical ones, the diminutions of 
tenacity at the respective points. 

In examining the eleventh and twelfth columns of Table XXIV., with a 
view to a relation which may afford a practical rule for calculating the 
strength of copper at any given temperature, it will be found, that with the 
exception of the three anomalous cases, Nos. 11. 14, and 17, of the table, 
they may be referred to a species of parabola, of which the ordinates repre¬ 
senting the temperatures above 32°, have to the abscissas representing the 
diminutions of tenacity, a relation expressed by the cube roots of the 
squares of the latter quantities ; or, in other words, that the squares of the 
diminutions are as the cubes of the temperatures .* 


* To determine whether any, and if any, what, single function of the tempera¬ 
ture will at any point express the diminution of strength, as compared with that 
observed at other points, it was not deemed expedient to rely on a single compari¬ 
son. The following method was, therefore, employed to obtain an expression cor¬ 
responding with each of fourteen different points, compared with thirteen others. 
Futtincr t = any observed temperature above 32° ; t' = any other temperature above 
the same ; d= the diminution of tenacity by the former temperature, and d! = that 
by the latter : also #=the power of the temperature, according to which the diminu¬ 
tion of tenacity varies, we have t x : t' x : : d : d' whence —=— from which we 

j* Jf di 

get x == ! j0 ^ d ~ dj0 ^ d .— Thus at a temperature offc^H^Fah., the tenacity was 
® Log t f — Log t. 

found by experiment to have been diminished .6691, its amount at 32° being 
1.0000; and its diminution at 492° was .2133; hence by the above formula. 
Log .6691— Log .2133 rnQ 

Log (984—32)— Log (492—32) 


7 





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77 


By applying the law above stated* and assuming the greatest diminution 
observed, or that obtained at 1000° above the freezing point, as a true 
standard of comparison, we get the calculated results contained in the 13th 
column of the table, and a comparison of that with the 12th, furnishes the 
differences in column 14th. This last, compared with the 9th, shows that the 
greatest deviations even of the anomalous experiments already noticed, do not 
amount to so much as the actual irregularities sometimes found in the metal 
at common temperatures, for while the highest numbers in the 14th column 
are less than four and one-tenth per cent, of the total strength, several of those 
in the 9th amount to more than four and a half per cent, of the same sum. 

The curve traced, (Plate IX.) represents the column of calculated 
results, and is continued to the opposite side of the figure to show to 
what point this law would lead as the temperature of no tenacity.t This 

* The following table exhibits the mean results of the several sets of comparisons 
with the temperature above 32°, at which each experiment was made, and the dimi¬ 
nution of strength corresponding, agreeably to the preceding note. 

TABLE XXV. 


No. of the compari¬ 
son. 

Temperature above 
32 degrees. 

Diminution from the 
ascertained strength at 
32 degrees. 

Mean value of x , 
by 13 comparisons at 
each point. 

Difference of each 
from the mean value of 
all the trials. 

1 

90.° 

.0175 

1.536 

+.036 

2 

180. 

.0540 

1.462 

—.038 

3 

270. 

.0926 

1.518 

+.018 

4 

360. 

.1513 

1.444 

—.056 

5 

450. 

.2046 

1.489 

—.011 

6 

460. 

.2133 

1.474 

—.026 

7 

513. 

.2446 

1.447 

—.053 

8 

529. 

.2558 

1.466 

—.034 

9 

660. 

.3425 

1.474 

—. 026 

10 

769. 

.4398 

1.570 

+.070 

11 

812. 

.4944 

1.565 

+.065 

12 

880. 

.5581 

1.542 

+.042 

13 

984. 

.6691 

1.557 

+.057 

14 

1000. 

.6741 

1.458 

—.042 


Mean of 14 means= 

=1.500=x 



Hence t 1 - 5 : t' 1 - 5 : : d : d', or t 3 : t' 3 : : d 2 : d ' 2 , which is the practical rule above 
given. 

-j- The application of the law deduced from the research in the preceding note, to 
the purpose of getting the column of calculated diminutions, as well as to that of 
extending the curve to the limit of tenacity, requires but a transformation of the pro- 


t' 


portion t 3 : t' 3 : : d 2 d' 2 into the equation - 


3_ d r 

d 


whence - 
’ t 


2 d' P 

=^-and d'=dx - 
d, t 


or "o {Logt'—Log /)+ Log d—Log d' . Thus to obtain the strength of copper at 

























/ 


78 

is seen to be 1333 degrees Fah. which is 663 degrees lower than any de¬ 
termination of the melting point of copper hitherto made. It is well known 
that metals in general pass, in coming to the state of fusion, through a con¬ 
dition, in which though disintegration is nearly or quite complete, fluidity 
is not fully established ; and in this granular state they, in some cases, con¬ 
tinue through a considerable range of temperature. The melting points 
are those at which fluidity is clearly established. But notwithstanding 
this fact, and the very close accordance of the law above mentioned, with 
the observed diminutions of tenacity, we do not venture to assert that the 
theoretical law which might be derived from operating on copper absolutely 
pure, and of uniform tenacity throughout the specimen, would not give a 
form so varied as to change the parabolic curve into one possessing a point 
of inflection. An inspection of the figure as well as a reference to the table 
in the preceding note, will be found to favour the supposition that the rate 
of increase in temperature corresponding to a given decrease of tenacity, 
does in fact pass through a minimum near the point where one-half of the 
absolute tenacity is overcome. The right hand branch of the curve indi¬ 
cates the probable course after inflection. 

Extensibility of Copper. 

In producing the rupture of bars of copper it became evident that this metal 
undergoes during the mechanical strain to which it is subjected, a degree of 
elongation dependent, in some measure on the temperature to which it is 
raised. The mode of ascertaining this point, consisted in measuring after 
the trial of each bar had been completed, the united lengths of all its frag¬ 
ments. In reconstructing the bars for this purpose, care was taken to bring 
the corresponding portions into as close a contact as possible, and also to 
allow by estimation for any imperfection in the same from roughness of the 
fracture. A second mode was, to select from among the fragments of each 
bar one or more which retained the original inch-marks, and which had at 
the same time, been apparently strained to the full extent of its resistance, 
without actually parting. By this latter method of trial it was ascertained 
that the extensibility of all the 8 bars with the exception of Nos. 6 and 7, 
was nearly uniform, varying only between 40 and 44 per cent, of the original 
length. A section measured on No. 6, gave the length between two inch- 
marks only 1.25 inch, and on No. 7, 1.28. The trials on both these sec¬ 
tions had been made at ordinary temperatures. When comparing the total 
lengths after fracture with the original length of each bar, we obtained as a 
general result, very nearly the same extension as when employing the seve¬ 
ral inch-marks as just stated. The mean elongation of the whole after 116 

1232° Fah., we have 1232°—32°=1200° .‘.Log 1200=3.0791821 

Log 1000=3. 

.0791821 

3 


2)2375463 

.1187731 

Add Log. 6741=—1.8287243 
Gives Log .8861=—1.9474964 

Hence 1.000—.8861=.1139 is the remaining strength ; or 11_A. per cent of the 
strength at 32°, is all that remains at 1232°, which is a visibly red heat in day light. 






Observed Mm'/mtioris or'tenacity ■ CulcubUed diminutions or' tmarity. 


Mao- JI. 






























































































































is 

ter 

tha 

dit. 

is ] 

tin 

are 



len, 

ger 









79 


iractures, was 43.5 per cent, of the original length. Other things being 
equal, the bars of least area appeared to have been most extensible. No. 2 
was stretched, by 18 fractures, from 30 to 46 j inches. No. 8, by 14 frac¬ 
tures, from 30 to 43 inches. But the circumstance of most importance is 
the temperature of the bar at the moment of trial. Thus on bar No. 7, 
(Table XXII.) the first fracture was made at 912° and the area of section 
afterwards was .744X .244=.181536 square inch, and the diminution from 
its original size only .002571, while at the thirteenth fracture, when 
the temperature was 81.5°, the area, after trial, was .550X.174=.095700, 
a diminution of .088316, or 34 times as much elongation as before. 

Strength of holler-iron at ordinary temperatures . 

The results of experiments on boiler-iron, at ordinary temperatures, will 
be found included in thirty-two tables, from XXVI. to LVII., inclusive. On 
some few of the specimens, the strength of which is exhibited in these 
tables, all the experiments were made with a particular view to the irregu¬ 
larities of the metal, and at, or near the same temperature, while on other 
bars much diversity in the objects of the experiments prevailed, and con¬ 
sequently of these, only a few trials can be selected which may be con¬ 
sidered entirely appropriate to the present topic. When making compari¬ 
sons with a view to the mean strength of sheet iron, even from the same 
plate, it is necessary to consider that the question may be answered differ¬ 
ently according to the direction in which the specimen was cut off; to the 
condition in which it was submitted to trial, whether rough from the shears, 
tiled to a uniform size, and smooth surface, or filed away in notches to 
overcome the influence of the shears ; or finally, according to the previous 
treatment of the specimens, whether subjected or not to annealing or other 
influences of heat after leaving the rolls. The tables furnish, under appro¬ 
priate heads, the information necessary to answer, separately, the several 
questions arising out of these different aspects of the subject. With re¬ 
gard to the method of preparing the specimens, by reducing them to an 
uniform size throughout the whole extent of the bar, it may be remarked, 
that on the forty-one bars of iron, which in the course of this report, are 
described as having undergone that preparation, there were measured 1049 
points, or sections, and there were made 517 fractures, showing, on an 
average, but little more than two inches between two adjacent points of 
fracture. It also appears that on only two of those bars (Nos. 220 A. and 
224 B.) did the mean area of all the points measured, correspond exactly 
with that of all the sections of fracture. On 22 bars the mean area of the 
fractured parts is less than that of the measured sections, by an average of 
.000340 of a square inch, and on 17 bars the mean section of fracture is 
greater than the mean measured sections by an average amount of .000187. 
This proves, what might indeed have been anticipated, that the fractures 
would, in general, take place at the smaller sections, and as the mean area 
was about.175 sq. inch, it appears that the difference between the measured 
and the fractured sections, due solely to irregularities of filing, that is, be¬ 
tween the condition of our specimens and that of others which should be ab¬ 
solutely uniform in size, amounts to not more than TT VVoo' or ijj'g P art o! 
the total strength. This portion is less than the irregularities in the struc¬ 
ture of rolled iron, as may be shown by referring to tables LV. and LVII. 

7* 


80 


TABLE XXVI. 


Experiments on iron bars No. 2,4,6 and 8. Manufactured by Messrs. 
Mason, Miltenberger 8f Co., at the Pennsylvania Iron Works, Pitts¬ 
burg, from Juniata piled iron. Nos. 2 and 4, cut lengthwise of the 


Number of the bar. 

Direction of the slit. 

Number of the experiment. 

DATE. 

Length before trial. 

Breadth. 

Thickness. 

Area of the section of fracture 

before trial. 

Temperature Fahrenheit. 

Breaking weight in the scale. 

Breaking weight X leverage. 

F rietion. 

2 

2 

Length. 

<C 

1 

1 

2 

1832. 

June 13. 

<< 

23.55 

.890 

.660 

.260 

.258 

sq.inch. 
.231400 

.170280 

o 

60 

79.5 

lbs. 

479 

378 

14370 

11340 

718 

567 

4 

Length. 

1 

ii 

23.6 

.980 

.256 

.250880 

65 

415 

12450 

622 

4 

<< 

2 

<4 

13.2 

1.030 

.260 

.267800 

65 

460 

13800 

690 

4 

(( 

3 

4 4 


.990 

.260 

.257400 

65 

493 

14790 

739 

6 

Cross. 

1 

(< 

21.25 

1.000 

.220 

.220000 

65 

444.5 

13335 

666 

6 

U 

2 

(4 

19. 

1.058 

.254 

.268732 

65 

493 

14790 

739 

6 


3 

44 

10.4 

1.054 

.260 

.274040 

65 

526 

15780 

789 

8 

Cross. 

1 

I 

44 

t 

21.2 

1.000 

1 

.252 

.252000 

1 

65 

443 

13290 

664 


i 








































































SI 


TABLE XXVI. 

f sheet , and 6 and 8 crosswise of the same. With the exception of 
< experiment No. 2, the trials were all made at original sectioyis. Speci- 
Ifc gravity , 7.7169. 


S3 

3 


o 

'U 

t: 

W 


lbs. 


13652 


10773 


11828 

13110 

14051 


12669 

14051 

14991 


12626 


U 

a 

G 

a* 

CO 

u, 

p* 

on 

g 

O 

P. 

0 


bp 

ri 

0> . 
h .a 

CO i 

s 


58997 


63266 


47146 

48955 

54588 


57587 

52286 

54704 


50103 


ci 

o 


v 

w 

bJO 


o 

CO +-> 

a 

Tr ^ 

S 

o 


u 


("224- 
J 336- 
448- 
460- 


U 


("280— 
j 236— 
J 392— 
1 448— 
| 474— 
L479— 


a 

-a 

4> 

O 


W 


“15 
“16 
“19 
“25 
“21.5 
Broke. 



("280— 

.20 


| 336— 

.22 


392— 

.15 > 

21.4 

430— 
^443— 

.15 

Broke. J 



U 

<D 

£ 

5u0 

C 

0) 

»-4 


<4-1 

(fl 

P 

O 

'■*-> 

a 

<L‘ 

co 

O 

oj 

<L> 

in 

< 


23.8 


23.85 


13.33 


21.75 


19.1 


.878X-240 

=.210720 


c .640 x -230 1 
l =.147200 5 


c .996X-220 > 
l =.219120 5 


.958X-226 
l =.216508 


REMARKS. 


C This fracture wasl 
made at a section 
deeply filed in the 
bar with square )> 
shoulders, perpen¬ 
dicular to the 
length of the bar. 


1.048X.232 

=.243136 


C 1.050X-234 l 
l =.245700 $ 


C .990X-228 l 
l =.225720 5 
















































82 


TABLE XXVII. 

Experiments on bar No. 3. Manufactured at the Pennsylvania Iron 1 
Works, by Messrs. Mason, Miltenberger, Co., at Pittsburg, from t 
Juniata piled iron—rolled into ? inch boiler-plate ; cut with the shears J 


Marks. 

Breadth. 

Thickness. 

Area before trial at 
the points measured. 

1 

BATE. 

No. of the experiment. 

Area of the section of 

fracture before trial. 

Temperature. Fah. 

Breaking weight ii 

the scale. 

Breaking weight mul¬ 

tiplied by leverage. 





1834. 






1. 

.757 

.242 

.183194 

Jan. 13. 

1 

.183194 

Co 

o 

346 

10380 

2. 

.757 

.242 

.183194 







3. 

.757 

.243 

.183951 

<< 

2 

.182979 

78 

354 

10620 

4. 

.757 

.243 

.183951 







5. 

.757 

.243 

.183951 

Jan. 18. 

o 

O 

.183194 

520 

356 

10680 

6. 

.75 9 

.241 

.182919 







7. 

.760 

.241 

.183160 

a 

4 

.184437 

572 

371 

11130 

8. 

.758 

.243 

.184194 







9. 

.756 

.243 

.183708 

a 

5 

.183951 

574 

379 

11370 

10. 

.759 

.242 

.182678 







11. 

.656 

.242 

.182952 

<c 

6 

.185074 

576 

399 

11970 

12. 

.754 

.242 

.182468 







13. 

.757 

.244 

.184708 

c 6 

7 

.183951 

76 

417 

12510 

14. 

.757 

.243 

.133951 







15. 

.757 

.242 

.183194 

i c 

8 

.183160 

76 

417 

12510 

16. 

.757 

.243 

.183951 







17. 

.759 

.244 

.185196 

ii 

9 

.183194 

76 

417 

12510 

18. 

.758 

.244 

.184952 







19. 

.759 

.243 

.184337 

<< 

10 

.183708 

76 

417 

12510 

20. 

.758 

.243 

.184194 







20.5 

.753 

.243|.182979 

if 

11 

.183043 

76 

440 

13200 

Mean of 14= 

=.183751 

ii 

12 

.183951 

| 

76 

440 

13200 


Maximum .185196 

a 

Mean of 12 

'.183653 





Minimum .182468 
Mean of the two .183832 
Diff. of the two .002628 



































S3 


TABLE XXVII. 


lengthwise of the sheet , and reduced by filing through 20.5 inches of its 
length. Specific gravity 7.7169. 


| Friction. 

Effective strain. 

Strength in lbs. per 
square inch. 

Point fractured. 

519 

9861 

53828 

No 

1. 

531 

10089 

55137 

66 

20$. 

534 

10146 

55389 

u 

2. 

556 

10574 

57331 

u 

19. 

568 

10802 

58722 

66 

3. 

598 

11372 

61445 

u 

17$. 

625 

11885 

64609 

u 

16. 

625 

11885 

64889 

66 

7. 

625 

11885 

64876 

66 

15. 

625 

11885 

64695 

66 

9. 

660 

12140 

68509 

66 

10*. 

660 

12540 

68170 

66 

14. 


REMARKS. 


Part in melted tin from 9 to 13—the 
fracture is 7 inches from the melted me¬ 
tal. 

Six inches from the heated part. 

Six inches from the heated part. 

Four and a half inches from the tin. 


The mean area of the sections of fracture 
is .000098 sq. in. less than the mean area of 
the measured sections. 





















84 


TABLE XXVIII. 

Experiments on bars Nos. 9, 10, and 11. Manufactured by Henry "'| 
S. Spang Sf Son, at the JEtna rolling mill, near Pittsburgh Pa. The j 
blooms made by Henry S. Spang, Huntingdon county, Pa. Ham- }> 
mered into slabs, and rolled into sheets. These bars, cut with the j 
shears lengthwise of the sheet. The fractures, made either at original J 


No. of the bar. 

Direction of the slit. 

No. oi the Exp t. 

DATE. 

Length before trial. 

Breadth before trial. 

Thickness before trial 

Area before trial. 

1 

"3 

pH 

CD 

w 

cj 

5 

P4 

g 

V 

h 

Breaking weight in 

the scale. 

Breaking weight mul¬ 

tiplied by leverage. 

1 

Friction. 

9 

Length. 

1 

1832. 
Sep. 19, 

23.7 

1.000 

.202 

.202000 

65.° 

373.5 

11205 

+560* 

9 


2 

ti 


.966 

.210 

.202860 

65. 

417. 

12510 

—625 

9 

ii 

3 

'v 

ti 


1.000 

.210 

.210000 

65. 

427. 

12810 

—640 

9 

tt 

4 

Sep. 26, 


.691 

.212 

.146280 

568. 

394. 

11820 

—591 

9 

ii 

5 

Oct. 3, 


.596 

.212 

.126352 

61. 

289. 

8670 

—433 

9 

ii 

6 

a 


.734 

.212 

.155608 

80. 

378. 

11340 

—567 

10 

Length. 

1 

1832. 
Stp. 19, 


.712 

.204 

.145248 

575. 

327. 

9810 

—490 

10 

ii 

2 

it 


.643 

.204 

.131172 

100. 

333. 

9990 

—499 

10 

it 

3 

Sep. 22, 


.693 

.204 

.141372 

73. 

320. 

9600 

—480 

10 

it 

4 

ii 


.650 

.201 

.130650 

574. 

294. 

8820 

—441 

10 

t i 

5 

ii 


.661 

.208 

.137488 

571. 

358. 

10740 

—537 

11 

Length. 

- 

1832. 
June 7. 

23.6 

1.000 

.204 

.204000 

70.75 

272. 

8160 

4-408 

11 

it 

2 

.< 

18.6 

.972 

.201 

.195372 

70.75 

348. 

10440 

—522 

11 

t< 

3 

“ 


.954 

.205 

.19557C 

70.75 

381. 

11430 

—571 































































85 


TABLE XXVIII. 




sections as the bar came from the shears , or at sections deeply filed on 
the edges with a semicylindrical file making two notches directly op¬ 
posite to each other; between the deepest parts of which the measure¬ 
ments were taken. Specific gravity 7.7874. 


Effective strain. 

!h 

<v 

p, 

QO 

a 

• 

—« 

bjO-^5 

5 % 

C/3 3 

cr 1 

Vi 

Length after fracture. 

Area of the section 
after fracture. 

REMARKS. 

11765 

11885 

58191 

58587 

24.5 

C.932X.190 1 
l =.177080 5 

f * The bar was broken with a rising mo- 
J tion of the lever, that is, by drawing up the 
] weight with the screw—hence the friction 
L(.05 of the weight) is to be added, 
c Broke at an original section near the 
£ wedges. 

12170 

57952 



C Broke at an original section near the filed 
< section, which now bore 59.462 lbs. per sq. 
(^in., its area being .997X .210=.205170. 

11229 

76763 



C This experiment made with great care, 
l continued one and a half hours. 

8237 

65191 




10773 

69232 


• 


9320 

64166 



Broke suddenly at the filed section. 

9491 

72355 



C The temperature recorded is approxi- 
< mate only, being derived from the heated 
(^heads, still warm from the last experiment. 

’ 9120 

64511 




8379 

64133 




10203 

74210 




8569 

9818 

42000 

50253 

23.9 

C.967X-167 1 
l =.161489 5 

C Fracture made with a rising motion of 

< the lever, the friction is therefore to be 
padded to the weight. 

C A section had been filed, the area of 

< which was .193570, but the bar did not 
break at that point. 

10859 

55529 


C.870X-161 l 
l =.140070 5 

£ Broke at the filed section above men- 
£ tioned. 







































86 


TABLE XXIX. 

Experiments on bar No. 14, cut from a sheet of boiler iron by a cross 
section. Manufactured at the jEtna Rolling Mill , near Pittsburg, by 
Henry S. Spang fy Son from blooms made by Henry S. Spang, in 






1 


O 

i 

a 

0) 

J3 





x 




•-1 

V3 

4-> 

a 

<i> 

c/J 

8 

<b 

r+ 

a . 

o ~a 

V3 % 

QJ ^ 

eo 2 

DATE. 

4-? 

P 

cu 

E 

4- .2 

^ p 

0) 

1 5 
d 

.SP 

*c 

< 

PQ 

IS 

1) 

© p 

ti 

<■5 

a 


cL 

X 

o 

o 

c cl; 
gj b 
£ 2 
<3 03 
& 

u 

V 

p, 

g 

E * 

KS 

<u 

Breaking 

scale. 

0 

.698 

.221 

.154258 






1 

.700 

.210 

.147000 






2 

3 

.700 

.695 

.214 

.215 

.149800 

.149425 

1833. 
Oct. 25 

i 

.157854 

77 

291 

4 

.697 

.218 

.151946 






5 

.697 

.216 

.150552 






6 

.697 

.212 

.147764 






/ 

.697 

.215 

.149855 

u 

2 

.155400 

732 

291 

8 

.696 

.221 

.153816 






9 

.695 

.221 

.153595 






10 

.695 

.221 

.153595 






11 

.697 

.221 

.154037 

44 

3 

.148287 

552 

291 

12 

.697 

.228 

.158916 






13 

.700 

.225 

.157400 






14 

.700 

.221 

.154700 






15 

.701 

.224 

.157024 

Oct. 30. 

4 

.160310 

59 

343 

16 

.700 

.224 

.156800 






17 

.700 

.222 

.155400 






18 

.700 

.228 

.159600 






19 

.700 

.232 

.162400 

44 

5 

.155400 

59 

322 

20 

.700 

.232 

.162400 






21 

.697 

.230 

.160310 






22 

.692 | 

.229 

.158468 

Nov. 7. 

c 

.150055 

63 

331 







Mean of 23 = 

.154746 







Maximum 

.162400 







Minimum 

.147000 


7 

.156476 

64 

340 

Mean of the two 

.154700 







. Difference .015400 

a 

8 

.153705 

64 

342 






Mean of 8= 

.154686 




\ 









































87 


TABLE XXIX. 


C Huntingdon County , Pa. Hammered into slabs , and rolled into sheets. 
■s Specific gravity of the specimen from which it was cut , 7.7874. 


Breaking weight X 
leverage. 

Friction. 

Effective strain. 

Breaking weight in lbs* 
per square inch. 

Point of fracture. 

REMARKS. 

8730 

436 

8294 

52542 

No. 12f 

Part in tin from 15$ to 18. 

8730 

436 

8294 

53378 

“ 17 


8730 

436 

8294 

55932 

“ 6i 


10290 

514 

9776 

60982 

“ 21 


9660 

483 ’ 

9177 

59054 

“ 13J 


9930 

496 

9434 

62870 

• 

“ 3i 


10200 

510 

9690 

61926 

“ 11$ 


10260 

513 

9747 

63413 

-471 

OO 

1 

The point of fracture had been 
crushed in the wedges in a former 
experiment. 

The mean of the 23 measurements 
taken before trial is greater than 
the mean of the 8 points of fracture 
by .000060 square inch. 


8 



















S8 


TABLE XXX. 


Experiments on bars Nos. 17,18. 21, 22 and 23. Manufactured by Messrs. H. S. Spang & Son, at the 
into slabs, and rolled. Specific gravity, 7.77. 


• 

S 

o 

Cm 

o 

© 

fc 

Direction of the 
slitting. 

No. of the exp’t. 

DATE. 

Length before 
trial. 

Ji 

M 

© 

M 

Thickness. 

Area of section 

before trial. 

*3 

p 

i—i 
© 

h 

Dr. weight in 

the scale. 

Br. weight X 

leverage. 

Friction. 

Effective strain. 

! i 

3 . 
s ”3 

zi 

zf*~ 

Z ©* 

— t/i 

55 £ 

17 

Cross. 

1 

1832. 
April 4, 

23.9 

1.024 

.260 

.266240 

59.° 

374 

11220 

+561 

11781 

44249 

18 

Cross. 

2 

U 


.986 

.264 

.260304 

59. 

415 

12450 

+622 

13072 

50218 

21 

L’glh. 

o 

O 

u 

24.1 

.984 

.252 

.247968 

69. 

336 

10080 

504 

9576 

38618 

21 

<< 

4 

« 

17.4 

.986 

.260 

.256360 

69. 

356 

10680 

534 

10146 

39578 

22 

L'gtb. 

5 

Sept. 29. 


.703 

.249 

.175047 

565. 

350 

10500 

525 

9975 

56984 

22 

4 6 

6 

Oct. 3. 


.720 

.257 

.185040 

581. 

430 

12900 

645 

12255 

66229 

22 

(C 

7 

U 


.626 

.255 

.159630 

90. 

260 

7980 

399 

7581 

47491 

22 

C( 

8 

Oct. 10. 


.683 

.255 

.174165 

68.25 

354 

10620 

531 

10089 

57928 

22 

6 6 

9 

u 


.687 

.257 

.176559 

515. 

O QO 

ooo 

11490 

574 

10916 

61826 

22 

<< 

10 

Oct. 25. 


.627 

.257 

.161139 

56.5 

315 

9450 

472 

8978 

55716 

22 

<< 

11 

Oct. 31. 


.675 

.260 

.175500 

90. 

347 

10410 

520 

9890 

56353 

23 

L’gth. 

12 

Oct. 31. 

24.3 

1.004 

.260 

.261040 

69. 

392 

11760 

588 

11172 

42798 

23 

U 

13 

u 

21.1 

1.020 

.260 

.265200 

69. 

426 

12780 

639 

12141 

45780 

23 

ii 

14 

Nov. 18. 


.736 

.264 

.194304 

394.5 

462 

13860 

693 

13167 

67765 

23 

u 

15 

U 


.775 

.252 

.195300 

87.5 

452 

13560 

678 

12882 

65960 

23 

u 

16 

U 


.713 

.256 

.182528 

87.5 

380 

11400 

570 

10830 

59333 










































































































89 


TABLE XXX. 

JEtna Works, near Pittsburg, from blooms made by H. S. Spang, of Huntingdon eounty. Hammered 


Wt. producing 
temporary elon¬ 

gation. 

Elasticity of the 
bar. 

f259 

23/ 


280 

22. 


294 

14. 


326 

17.5 


<( 336 ' 

21. 

y 

350 

24. 


364 

31.5 


371 

27. 


L374Broke. J 


f392 

32. ^ 


403 

37.5 


412 

39. 


415 

26- 


< 415B.p , tiyofF. 

> 

Elas.af. 

par.fi. 


130— 

14. 


214— 

18.5 


J>77Fin.br.ofF.^ 


224— 

17. 


f280 
! 321 


25. ^ 

26. I 


1 336 28. 


L356 Broke. 



C t 

1 ) 3 


24.1 


24.4 


17.8 


CJ i) 
4) ej 

(/> L. 
0; *►« 


cs ci 
o 




.980X-256 ? 
=.250880 5 


i 


.966x -236 
=.227976 


.970 X-240 
=.232800 


24.4 


21.45 


1.004x-240^ 
=.240960 5 


.996x -254 ? 
=.252984 5 

.660x21 61 
=.142560 5 


REMARKS. 


f Broke with a rising* motion which makes 
J the friction conspire with the weight in 
i producing the frafcture. Hence the sign+ 
Lin the column of friction. 


r After the bar had been for some time 
strained with 415 lbs., the process was 


< 


arrested for the purpose of trying the 
elasticity under less weight. The re¬ 
maining strength, it appears, was 277 lbs. 
277 9 

=-Q 7 r==-j-y nearly; or about 64 per cent, 
of the original strength. 

- o o 


C The bar broke at once, on applying by 
) mistake, 336 lbs. It is probable that this 
\ point was extremely weak’d by the shears, 
Lor by straightening it, after being cut. 

c Broke with a slow and regular applica- 
i tion of weights. 


$ 


Do. This and the 6 following experi¬ 
ments were made on deeply filed sections. 


The fracture took place soon after add¬ 
ing the weight recorded. The experi¬ 
ment is, however, considered a fair one. 


i 


A flaw appeared in the edge, but before 
the final separation 8 or 9 pounds more 
were necessary .—Original section. 

Broke at a section not filed. 


Filed section. 

Do. 

Do. 










































90 


TABLE XXXI. 

Experiments on bar No. 16 boilerplate . Manufactured by Henry S. 
Spang fy Son f at the JEtna Rolling Mill, near Pittsburg, Penn. The 
blooms made by Henry S. Spang, Huntingdon County, Pa. Ham- 


ri 

u 

t2 

& 


a 

v 


o 

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 
11 
12 

13 

14 

15 

16 

17 

18 

19 

20 
21 
22 


<v 

& 


PS 

o 

2 

h 


.750 

.747 

.738 

.742 

.744 

.750 

.750 

.749 

.749 

.747 

.747 

.747 

.747 

.746 

.746 

.750 

.750 

.750 

.750 

.751 

.750 

.750 

.750 


.212 

.212 

.210 

.202 

.202 

.202 

.202 

.206 

.203 

.200 

.197 

.197 

.189 

.188 

.187 

.184 

.184 

.183 

.183 

.190 

.191 

.194 

.188 


•*-> 

a 

V) 

s . 

o 

£ « 
8 * 

o rH 

S £ 

~ r* 

<•3 

p. 


.159000 

.158364 

.154980 

.149884 

.150288 

.151500 

.151500 

.154294 

.152047 

.149400 

.147159 

.147159 

.141183 

.140248 

.139502 

.138000 

.138000 

.137250 

.137250 

.142690 

.143250 

.145500 

.141000 


Mean of 23 .146497 


Maximum .159000 
Minimum .137250 


The mean area of Iht 
23 measmed sections is 
001697 sq. inch greater 
than that of the 11 sec¬ 
tions of fracture. 


o> 

p. 

x 

W 


o 

£ 


2 

3 

4 

5 


Mn. of the 2.148125 
Diff. of the 2 .021805 


10 

11 

Experiments on bar No. 13 from 
the same specimen as the above. 
Length before trial 23.45. 

Br. 

.884 

.880 

Th. 

.212 

.212 

Experiment on No. 15 of which 
the length was 24 inches. 

.954 

.212 


1833. 

Oct. 19. 


DATE. 


u 


u 


Oct. 24. 


Oct. 26. 


U 

u 


Area of the section of 

fracture. 

Temperature Fahren¬ 

heit. 

Breaking weight in the 

scale. 

Breaking weight X le¬ 

verage. 

.139999 

57.5° 

263 

7890 

.151500 

636 

266 

7980 

.154294 

58 

308 

9240 

.147159 

58 

323 

9690 

.150086 

60 

323 

9690 

r 

.137250 

766 

264 

7920 

.137250 

644 

264 

7920 

.153281 

72 

338 

10140 

.138000 

72 

322 

9660 

.140877 

72 

304 

9120 

.143110 

72 

306 

9180 

.144800 




.187408 

65 

332 

9960 

.186560 

65 

336 

10080 

.202248 

65 

356 

10680 


- 


























































I 


91 


TABLE XXXI. 

mered into slabs and then rolled into sheets. This bar was cut across 
the direction in which the sheet passed the rolls ; reduced by filing, and 
gauged at every inch, from 0 to 22. Specific gravity, 7.7874/ 


e 

o 

o 

£ 

Effective strain. 

Strength in pounds per 
square inch. 

Wts. producing tempo¬ 
rary elongation. 

Elasticity. 

Point fractured. 

394 

7496 

53543 



No. 13* 

399 

7581 

50039 



“ 53 

462 

8778 

56887 



“ 7 

484 

9206 

62558 



“ 10 

484 

9206 

61338 



“ 34 

396 

7524 

54819 



“ 17| 

396 

7524 

54819 



“ 173 

507 

9633 

63852 



“ 2* 

483 

9177 

66500 



“ 16 

456 

8664, 

61500 



“ 183 

459 

8721 

60939 



“ 193 




T280 

0°..32' A 

Areas after fracture. 

498 

9462 

50488 

< 310 

0 ..29 C 

. 860 X • 194=. 166840 

504 

9576 

51329 

L 332 

0 ..31 _) 

.862X* 18=. 15516 

534 

10146 

50166 

280 

329 

0°53' 

0 40 

.946x. 190=. 179740 


REMARKS. 


< 


Part in tin from 4 to 7, Fracture 
f in the melted metal. In taking the 
I temp., with the pyrometer, a few 
grains of tin accompanied the stand- 
. ai d piece, but were afterwards ta- 
I ken out and found to weigh 24°, 
I which being added to the observed 
'"-deficiency gave400 + 212 + 24=636°. 


< 


Broke with the same weight as the 
preceding, 

’ The part in melted metal from 16 
1-2 to 191-2; after having tried the 
temp, as the bar was stretching, and 
obviously ready to break, removed 
the furnace and took out the tin, 
suspended the weight on it for two 
days, after which the breadth was 
taken at the narrowest part, and 
found to be .691 inch instead of .750 
Las at first. 

r Same part in as above. The heat¬ 
ing was now repeated, but instead of 
allowing the furnace to continue 
fixed, it was lowered when the bar 
began to stretch until the motion 
was retarded and then again brought 
up ti 11 it was renewed, and so on two 
o r three times, to avoid heating the 
standard piece higher than was ab¬ 
solutely necessary to break the bar. 


Had been near the hottest part. 
Blue from heat. 


< 


r Broke at a part annealed. Th» 
4 length after fracture was 23.8, show- 
(_ ing very little extension. 

Broke in two places 2 inches apart. 


Broke at the filed section, but not at 
the smallest part, showing an evident 
want of uniformity in strength. 
Length after fracture, 24.5. 


8 * 








































92 


TABLE XXXII. 

Experiments on bar No. 19. Manufactured by Henry S. Spang 30 
Son , from blooms made by Henry S. Spang , Huntingdon county, Pa. > 
Hammered into slabs , fled and rolled into plate. This strip was cut J 


Marks. 

Breadth. 

Thickness. 

Area before trial. 

DATE. 

No. of the experim’t. 

Area of the section of 

fracture. 

Temperature, Fah. 

Breaking weight in 

the scale. 

- - .— ■ 

Breaking weight X 

leverage. 

1 

.760 

.250 

.190000 

1833. 






2 

.754 

.251 

.189254 

June 22, 

i 

.189128 

576° 

326 

9780 

3 

.757 

.255 

.193035 







4 

.754 

.252 

.190008 



✓ 




5 

.756 

.248 

.187488 







6 

.755 

.249 

.187995 







7 

.754 

.251 

.189254 

U 

2 

.190000 

570 

378 

11340 

8 

.756 

.250 

.189000 







9 

.753 

.252 

.189756 







10 

.755 

.250 

.188750 







11 

.754 

.251 

.189254 







12 

.754 

.253 

.190762 







13 

.756 

.252 

.190512 

June 29, 

O 

O 

.188750 

77 

290 

8700 

14 

.758 

.253 

.191774 







15 

.758 

.252 

.191016 







16 

.756 

.251 

.189756 







17 

.757 

.246 

.186222 

U 

4 

.189567 

77 

296 

8880 

18 

.756 

.245 

.185220 







19 

.757 

.248 

.187736 

u 

5 

.187995 

77 

305 

9150 

20 

.753 

.246 

.185238 







21 

.773 

.244 

.188612 

u 

6 

.187488 

77 

315 

9450 

Mean of 21 = 

.189078 

u 

7 

.189254 

77 

319 

9570 


Maximum .193035 

u 

8 

.190595 

72 

234 

7020 


Minimum .185220 











u 

9 

.185470 

72 

267 

8010 

Mean of the 2= 

.190627 







Diflf. of the 2 = 

.007815 

« 

10 

.186478 

72 

291 

8730 





u 

11 

.186487 

73 

314 

9420 





u 

12 

.191774 

73 

290 

8700 





u 

13 

.187989 

73 

291 

8730 

V 

1 





Mean of 13 = 

.188536 





4 









































93 


TABLE XXXII. 

f with the shears in a direction crosswise of the sheet, reduced to a nearly 
< uniform size by filing. Specific gravity 7.7764. 




3 

Gi 





tfi 




13 

Sh 

rj 

Qj 

Ih 


G 

_o 

CO 

0) 

> 

• H 
•M 

• r* * 

60.5 

■*-> 

O 

c$ 

d 

REMARKS. 

w 

a 

•c 

a 

£c 

P 2 

rj cJ 

.S 

’3 


fa 


CO 

p. 






f In tin from 9* to 13. The bar, on being 

489 

9291 

49125 

No. 10# 

J strained, manifested an unequal extensi- 
} bility in the three different laminae of which 
Lit was composed. 





f Part now in tin is from 2* to 6*, the 





1 length of the part embraced between the 

567 

10773 

56700 

“ 1 

J two heads is 8 inches. On raising the 
\ temperature from 180° to 510°, under a 
| strain of 326 lbs. the index fell 1° 05' on 
Lthe arc. 





C Broke at a part previously griped by the 

435 

8265 

43788 

“ 10 

< wedges. This and the subsequent trials 
C were on annealed portions. 

444 

8436 

44501 

00 


457 

8693 

46187 

“ 6 


472 

8978 

47886 

« 5 


478 

9092 

48041 

“ 2 


351 

6669 

34990 

“ 12# 


400 

7610 

41031 

“ 17# 


436 

8294 

44477 

« m 


471 

8949 

47987 

“ 19* 


435 

8265 

43098 

“ 14 




v. 



436 

8294 

44120 

“ 16* 

The mean area of fracture is less by .000542 





square inch than the mean area of the mea- 
|sured sections. 


















94 


TABLE XXXIII. 

Experiments on bars NoNz 5, 27, 30, 32, 35, 37, 39 and 41. Manu-~\ 
factured at the Sligo Iron Works, Pittsburg, by Barnet Shorb,from Ju- l 
niata blooms, piled and rolled into boiler-plate. Nos. 25 and 27 were . 
cut lengthwise from a quarter-inch sheet, and Nos. 30 and 32, crosswise J 


No. of the bar. 

Direction of the slit. 

DATE. 

No. of the experim’t. 

Length before trial. 

Breadth. 

Thickness, 

Area of the section of 

fracture before trial. 

Temperature, Fall. 

Breaking weight in 

the scale. 

Breaking weight X 

leverage. 

Friction. 

25 

Length, 


1 

24.1 

1.000 

.238 

.238000 

69.° 

370. 

11100 

555 

25 

u 


2 

19.2 

1.022 

.240 

.245280 

69. 

378. 

11340- 

567 

25 

a 


3 

17.4 

1.072 

.236 

.252992 

65. 

410. 

12300 

615 

25 

u 


4 


1.093 

.234 

.255762 

65. 

413. 

12390 

619 

25 

u 


5 


1.080 

.252 

1 

.250560 

65. 

416. 

12480 

624 

25 

U 


6 


1.107 

.232 

.256824 

65. 

439. 

13170 

658 

27 

Length, 


7 

24.2 

1.012 

.204 

.206448 

62.5 

403. 

12090 

604 

35 

Length, 


8 

23.15 

1.092 

.214 

.233688 

59. 

354.5 

10635 

531 



1832. 










37 

Length. 

May 15, 

9 

22. 

.480 

.220 

.105600 

73.5 

171. 

5130 

256 

30 

Cross, 


10 

22.9 

.874 

.240 

.209760 

62.5 

329. 

9870 

493 

32 

Cross, 


11 

23. 

1.060 

.234 

.248040 

60. 

410. 

12300 

+647 

39 

Cross, 


12 

23.5 

1.040 

.214 

.222560 

73.5 

317. 

9510 

475 

41 

Cross, 


13 

23.35 

.994 

.222 

* 

.220668 

73.5 

292. 

8760 

438 







































































































95 


TABLE XXXIII. 

"from the same. Nos. 35 and 37 were taken lengthwise , from a three - 
sixteenth inch-sheet; 39 and 41, crosswise from the same. The specific 
gravity of the first four was 7.764, and of the other four , 7.7954. 


Effective strain. 

Strength in lbs. per 
square inch. 

Weight producing 

temporary elongation. 

Elasticity of the bar. 

Length after trial. 

Area of section after 

fracture. 

REMARKS. 

10545 

10773 

11685 

11771 

11856 

12512 

44307 

43921 

46186 

46023 

47319 

48718 

C224 
< 361 
(.370 

39. } 

28.5 C 
Broke, j 

24.4 

19.9 

.980X-210 ? 
1 =.205800 5 

C -978X-214 } 
l =.209292 5 

C1.014X-195 1 
1 =.197730 5 

C1.066X-203 
i =.216398 5 

C1.060X-189 ? 
i =.200340 5 

C1.103X-196 l 
1 =.216188 5 

C Broke at the smallest sec- 
X tion. 

Broke at an unfiled section 

C Broke at an original sec- 
J tion. A section had been 

1 filed to the area of 1.044X 
L.234=.244296. 

11486 

55636 

f224 

J 336 
i 392 
[403 

35. ^ 

38. 

53. 

Broke. 


24.4 

C .986X-196 l 
l =.193256 5 

Br. at an original section. 

10104 

43237 



23.2 

C 1.088X-204 l 
l =.221952 5 

C Br. at an original section 
X —no filing on this bar; 

4874 

46155 

rii2 

< 162 

071 

33. } 

43. C 
Broke, j 

22.1 

C . 440 X* 202 l 

1 =.088880 5 

C A narrow strip. Broke 
X at an original section. 

9377 

44703 



23.1 



12947 

52197 

fll2 

168 

224 

d 280 
336 
392 
1410 

10.5 ^ 
10. 

12. 

13.5 
16. 

17. 

Broke. ^ 

> 

23.1 

Cl.044x.216 l 
l =.225504 5 

r Br. with a rising motion 
of the lever, that is, while 
, taking up the weight by the 
] force of the screw—the fric¬ 
tion is therefore positive & 
one-nineteenth of the wt. 

9035 

40595 

T224 
< 315 
C.317 

20. A 
31. C 
Broke, j 

23.65 

C1.020X.204 l 
l =.208080 S 

C The lamellated structure 

I was exhibited by the differ- 
■i ent port’ns in the thickness, 
having separated for more 
Lthan 4 inches near the frac. 

8322 

37713 

T224 
< 282 
C292 

45. } 

27.5 C 
Broke, j 

23.85 

C .948X-216 l 
l =.204768 5 

6 This bar had been cut from 
[ the same specimen as the 

J preceding and broke in the 
>1 same manner, viz. with a 
j flaky separation of the la. 
laminae. 






































































96 


TABLE XXXIV. 


Experiments on bars No. 42, 43, 44, 46 and 48. Manufactured by 
H. Blake Co ., Pittsburg. The first three were made by puddling , 
from pigs obtained at the Kentucky Iron Works , Greenup co., Ky. 
The last two were rolled from Juniata blooms , previously hammered 


> 


No. of the specimen. 

Direction in which it 
was cut from the sheet. 

Mode of manufacture. 

DATE. 

No. of the experim’t. 

Length of the bar be¬ 
fore trial. 

Breadth of the section 

of fracture before trial. 

Thickness before trial. 

Area of the section 

before trial. 

Temperature, Fah. 

Breaking weight in 

the scale. 

Breaking weight X 

leverage. 

Friction. 




1832. 










42 

Length, 

Puddled, 

May 12, 

1 

23.8 

.970 

.252 

.244440 

73.5° 

443 

13290 664 

42 

a 

u 


2 

22.45 

.980 

.252 

.246960 

73.5 

452 

13560 

678 

42 


tt 


3 

00 

00 

r«H 

.978 

.252 

.246456 

73.5 

462 

13860 

693 

43 

Length, 

Puddled, 

u 

4 

23.2 

1.140 

.250 

.285000 

73.5 

441 

13230 661 

44 

Length, 

Puddled, 

il 

5 

23.7 

1.048 

.254 

.266192 

(73.5 

503 

15090 

754 

44 

u 


u 

6 

17.9 

1.048 

00 

c* 

.259904 

73.5 

507 

15210 

760 

46 

Length, 

Hammer¬ 
ed plate, 

(i 

7 

24.4 

.624 

.242 

.151008 

00 

CO 

314 

9420 

471 

46 


(t 

a 

8 

19.8 

.624 

.242 

.151008 

68. 

324 

9720 

486 




1832. 










48 

Length 

Hammer¬ 
ed plate, 

May 19, 

9 

24.5 

.976 

.246 

.240096 

73. 

503 

15090 

754 

48 

u 

(t 


10 

21.9 

1.010 

.246 

.248460 

73. 

518 

15540 

777 










































































97 


TABLE XXXIV. 

"into slabs , and constituting “ hammered plate.” 77iese were «// 

cut lengthwise of the sheets from which they were taken. The specific 
) gravity of 42, 43 and 44, ivas 7.682; that of 46 and 48, was 7.6785. 


.2 

*3 


> 

w 

o 

5a 


12626 

12882 

13167 


3 

o 

p. 


O 

a 


to I 

r* C3 

g g. 

CO ^ 


51653 

52162 

53425 


12569 


14336 


14450 


44102 


« a 
•a v 

'3-^ 

^ c3 


33 <p 

"2 3 
£ > 


W3 


CO 

'p 

V 


£ 


a 


o 


cS 

s 



53836 


55597 


8949 

9234 


59262 

61149 


441 


'"224 
336 
, 448 
' 476 
496 
v.503 


25. 


25. 

25. 

23. 

36. 

34. 

Broke. 


<»< 

c3 

jz 
—■ 

be 

a 

01 

i-! 


23.9 


22.55 


18.9 


a 


2 • 

£ g 

, 3 

O O 
ci 
d Cm 
g V, 

ci 


23.35 


>- 




f224 
! 280 
297 


L314 


*7 


14336 59710 


14763 


59418 


1 


f224 

336 

425 

444 

464 

478 

487 

503 


29. 

29. 

28.5 , 
Broke. J 


V 


24.1 


18.0 


{ 


1.036X-242 

=.250712 


24.8 


20.1 


16. 
18. 
21.5 

30. 

27. 

31. 

28. 

Broke. 


> 


25.2 


22.15 


{ 

{ 


.570X-210 

=.119700 

. 578 X. 206 
=.119068 


{ 


.896X.194 

=.173824 


. 968 X-204 
=.197473 


C .960X.236 7 
l =.226560 5 

C .960X.236 7 
l =.226560 5 

C .970X.236 7 
l =.228920 3 


C 1.120X.236 7 
£ =.264320 3 


REMARKS. 


f" This fracture exhibited, in 
7 some parts, a smooth steel-like 
7 appearance, and in others a re- 
C.semblance to cast iron. 


Broke at an original section. 


Do. 


Do. 


C 1.010X.228 7 
I =.230280 3 


H 


1 

1 


f Did not break at the smallest 
l section. 


The thickness at the point of 
fracture had probably been re- 
.duced by the former strain. 


Broke at a section deeply filed. 


1 

} 


Broke at a filed section. 


Original section. 































































98 


TABLE XXXV. 


Experiments on bars No. 51, 53, 56, and 58. Manufactured by 
Henry Blake Co ., of Pittsburg. Cut crosswise of the sheets from 
which they were taken , the first two (51 .and 53) from a boiler-plate of 


No. of the bar. 

<v 

■*-> 

Cm 

O 

a 

.2 

o 

0 ) 

5 4-> 

• M 

GO 

Mode of manu¬ 
facture. 

1 £ 

tt 

0 

0 )’ 

-C 

•M 

Cm 

O 

o 

fc 

DATE. 

Length of the 
bar before trial. 

Breadth. 

Thickness. 

Area of the sec¬ 

tion of fracture 
before trial. 

-a 

OS 

P< 

g 

<u 

H 

Breaking w’t. 

\ 

Breaking w’t. 

X leverage. 

Friction. 

51 

Cross. 

Ham’ed. 

1 

1832. 
May 19. 

24, 

.874 

.258 

.225492 

73 

472 

14160 

708 



U 

2 

<C 

21.5 

,830 

.258 

.215140 

73 

472 

14160 

708 

53 

Cross. 

Ham’ed. 

3 

u 

24. 

.972 

.250 

.243000 

73 

478 

14340 

717 

« 


a 

4 


21. 

.956 

.262 

.250472 

73 

500 

15000 

750 

56 

Cross. 

Puddled. 

5 


23,7 

.918 

.248 

.227664 

73 

471 

% 

14130 

706 

U 

U 

« 

6 


20.3 

.944 

.258 

.243552 

73 

495 

14850 

742 

58 

Cross. 

Puddled. 

7 

May 26. 

23.7 

1.044 

.244 

.254736 

62.5 

452 

13560 

678 

U 

« 

11 

8 

it 

22.35 

.986 

.256 

.252416 

62.5 

479 

14370 

718 

U 

U 

a 

9 

C 4 

20.7 

1.002 

.258 

.258516 

62.5 

496 

14880 

744 

u 

u 

a 

10 

June 30. 


.738 

.253 

.186714 

394 

471 

14130 

706 

u 

u 

« 

11 

« 

. 

.706 

.246 

.173676 

81 

448 

13440 

672 

u 

u 

u 

12 

K 


.696 

.257 

.178872 

81 

429 

12870 

643 












































































99 


TABLE XXXV. 


{ 


of Juniata hammered , and the other two, from one of Kentucky puddled 
iron. The specific gravity of the former, 7.7567, that of the latter, 


7.6511. 


C 

*3 


o 

> 
. ** 

_ 

.OJ 

ta 

W 


13452 


13452 


13623 


14250 


13424 


14108 


12882 

13652 

14136 

13424 

12768 

12227 


£ J 
o 

.a 

W u 

tOctf 

c a 

i * 
“ 33 


59656 


62527 


.5 &> 

V G 
3 O 

'S'S 

S 

tn © 

£ S 1 

V 


f224 
1 336 
-< 448 
| 464 
L472 


56062 


56892 


58964 


57926 


50570 

54085 

54681 

71896 

73516 

68356 


f 224 
I 336 
<< 448 
464 
478 
C 494 
( 500 


M 

u 


T224 
J 336 
) 448 
i_471 


C 448 
( 495 


Zj 


C*H 

O 


w 3 





25 

Broke. 


{ 224 
336 
392 
448 
452 

•< 


448 

479 


C 479 
(496 


49 
54 

50 
44 

Broke. J 
26 

Broke. 
57 

Broke. 




3 


J3 

e U 

3 3 

Cl 


24.5 


21.6 


24.45 


21.4 


23.83 


20.35 


23.8 

22.45 

20.8 


s 

O 

!«• 

C £ 

C3 rj 

QJ 

U U 


C. 828 X.224 > 
( =.186472 5 

C.800X.230 7 
I =.184000 3 


REMARKS. 


C.948X.224 7 
( =.212352 5 

C.916X.234 7 
l =.214344 3 






.898X-234 

=.210132 


. 926 X-244 
=.225944 


1 


1.030X-214 7 
=.220420 3 


C.980X.238 
( =.233240 


{ 

C.978X.234 7 
I =.228852 3 

C.715X-224 7 
I =.160160 3 

The mean area by 
10 trials is 87.8 per ct. 
of the areas of the 
same sections before 
trial. 


Broke at the smallest section under 
the same weight which had broken 
the larger section in the first expt. 


Did not break at the Jiled section. 


do. 


do. 


Two different sect’s, had been 
filed, one near the middle, ano¬ 
ther near the end of the bar. The 
_frac. now took place at the latter. 

r This section had been near the 

I middle of the bar in the preceding 
trial. The fracture was not now 
made in the narrowest part of the 
J filed section. The breadth of that 
’ part after the fracture was .906, 
its thickness .258. Calculating for 
the same breaking weight on the 
narrowest part the strength exhi¬ 
bited was 59604. 


Broke near the wedges. 


f This and the two preceding ex¬ 
periments were on sections not 
j filed, the three following were on 
^ filed sections intended to indicate 
the degree of weakness produced 
by the shears. 

Broke suddenly in hot oil. 

f The weight was raised from the 
| floor by the screw,and subsequent- 
! ly taken up by the windlass still 
; higher, but on letting it down a- 
gain the bar broke. Result doubt¬ 
ful. 

Broke short at the filed section but 
not so suddenly as in the 10th expx 


9 




































100 


TABLE XXXVI. 


Experiments on bars No. 59, 60, 61 and 62. Manufactured by M.! 
Blake Sr Co., Pittsburg, by puddling and rolling into boiler-plate. The l 
pig « obtained from the Kentucky Iron Works, Greenup county, Ky. J 


No. of the bar. 

Direction of the 
slit. 

DATE. 

No. of the exp’t. 

Length before 
trial. 

Breadth. 

Thickness. 

Area of the sec¬ 

tion of fracture 
before trial. 

1 

Temperature. 

Fahrenheit. 

Breaking weight 

in the scale. 

Breaking weight 

X leverage. 

Friction. 

i 

Effective strain. 

59 

Length, 

1832. 
May 23, 

1 

23.51 

.906 

.168 

.152208 

66.° 

258 

7740 

387 

7353 

60 

Length, 

Nov. 22, 

2 

23.55 

.550 

.170 

.093500 

59.75 

200 

6000 

300 

5700 

60 


ii 

3 


.550 

.170 

.09350© 

567.5 

240 

7200 

360 

6840 

60 

u 

Nov. 24, 

4 


.545 

.172 

.093740 

54. 

193 

5790 

289 

5501 

60 

u 

<t 

5 


.523 

.171 

.089433 

558. 

226 

6780 

339 

6441 

60 

tt 

a 

6 


.569 

.175 

.099575 

61.5 

212 

6360 

318 

6042 

60 

tt 

tt 

7 


.527 

.168 

.088536 

61.5 

191 

5730 

286 

5444 

61 

Length, 

May 23, 

8 

23.6 

1.048 

.182 

.190736 

66. 

336 

10080 

504 

9576 

61 

u 

June 27, 

9 


1.030 

.184 

.189520 

82. 

364 

10920 

546 

10374 

61 

u 

a 

10 


1.057 

.178 

.188146 

394. 

349 

10470 

523 

9947 

61 

tt 

n 

11 


1.051 

.179 

.188129 

82. 

378 

11340 

567 

10773 

61 

tt 

n 

12 


1.020 

.172 

.175440 

82. 

378 

11340 

567 

10773 

61 

ii 

tt 

13 


.945 

.170 

.160650 

394. 

349+ 

10470 

523 

9947 

62 

Length, 

July 18, 

14 


.697 

.184 

.128248 

580. 

315 

9450 

472 

8978 

62 

a 

ii 

15 


.683 

.186 

.127038 

570. 

298 

8940 

447 

8493 

62 

a 

a 

16 


.722 

.177 

.127794 

574. 

329 

9870 

493 

9377 

62 

a 

a 

17 


.700 

.177 

.123900 

82. 

278 

8340 

417 

7923 

62 

n 

tt 

18 


.676 

.182 

.123032 

82. 

252 

7560 

378 

7182 

62 

tt 

ii 

19 


.680 

.180 

.122400 

82. 

261 

7830 

391 

7239 

62 

tt 

ii 

20 


.727 

.181 

.131587 

82. 

266 

7980 

399 

7581 















































101 


TABLE XXXVI. 

f A part of the experiments made upon original sections , others on filed 
■s sections , in which nearly one-half of the original breadth of the bar was 
(_taken away . Specific gravity 7.6013. 


Strength in lbs. 

per square inch. 

Weight produc¬ 

ing temporary e- 
longation. 

Elasticity of the 

bar. 

Length after 
fracture. 

Area of section 
after trial. 

REMARKS. 

48308 

fll2 
| 168 

-< 224 
| 242 
(.258 

12.5' 
20. 1 
27. > 

27. 

Broke. J 

- 23.7 

C .888X.152 l 
1 =.135376 $ 

Broke at a section not filed, in the mid¬ 
dle of the bar. 

60963 

73155 

58684 

72021 

60678 

61489 




- 

i Began with a filed section near one end 
l of the bar. 

( This section was about seven inches 
( from the preceding. 

\ This section is the part between the two 
( preceding. 

C Temp, had been as high as 572° ; having 
< lowered the lamp, it fell at the moment of 
( fracture to the point noted. 

Piled section as above. 

Do. 

50211 

54738 

52869 

57264 

61405 

61917 

f224 
1 280 
<( 326 

1 332 
L336 

40. "'I 

42. | 

38. > 

36. | 

Broke.J 

23.65 

C 1.024X* 166 I 
l =.169984 $ 

(~ A section had been filed in the bar, 

| which appears not to have been deep 
} enough, as it did not break there. The 
] elasticities were repeatedly taken under 
| each weight, and are considered very ac- 
L curate. 

f Broke at once under the weight noted. 

< The bar had now a filed section of .945X 
( .170=.160650. 

f Broke out of the filed section—which 
■? was the same as in the preceding experi- 
( ment. 

f The strength of the filed section must 
be above 10773-f .16065=67058 lbs., for that 
\_section was not broken, 
f This calculation shows how much per 
<( sq. inch was borne by the filed section in 
^experiment tenth. 

70005 

66854 

73385 

63947 

58375 

59142 

57612 





Broke immediately on applying the 
weight noted in the table. 







































102 


TABLE XXXVII. 

Experiments on bars No. 64, 65, 68,70, 71 and 73. Manufactured by H. Blake & Co. of Pittsburg 
The first two made by the process of puddling—the pigs obtained from Greenup county , Kentucky; > 
the other four hammered into slabs from Juniata blooms, and then rolled into boiler-plate. The fractures j 


No. of the bar. 

Direction of 

the slit. 

Mode of man¬ 
ufacture. 

DATE. 

No. of the exp. 

Length be¬ 
fore trial. 

1 

Breadth. 

Thickness. 

Area of the 

section of frac¬ 

ture before 
trial. 

Temp. Fah. 

Br. weight in 

the scale. 

Br. weight X 

leverage. 

1 

Friction. 

Effective 

strain. 

Strength in 

lbs. per square 

inch. 

68 

Length, 

Hammered 

plate. 

1833. 
Jan. 5. 

1 

24.0 

1.096 

.202 

.221392 

62° 5 

450 

13500 

675 

12825 

57929 

68 

It 

tt 



2 

20.8 

1.008 

.200 

.201600 

62.5 

455 

13650 

682 

12968 

64325 

70 

Length, 

Hammered 

plate, 


3 

23.9 

1.054 

.214 

.225556 

65. 

377 

11310 

565 

10745 

47638 

64 

Cross, 

Puddled, 


4 

24.2 

1.018 

.208 

.211744 

73. 

335 

10050 

502 

9548 

45092 

65 

Cross, 

Puddled, 



5 

24,25 

1.012 

.200 

.202400 

65. 

364 

10920 

546 

10374 

51255 

65 

tt 

tt 

Ja. 

12. 

6 


.580 

.189 

.109620 

46.5 

242 

7260 

363 

6897 

62917 

71 

71 

r Cross, 

03 *■ 

u, 03 

S 

5 p. 

X 

tt 



7 

8 

24.1 

23.1 

1.024 

1.032 

.164 

.170 

.167936 

.175440 

62.5 

62.5 

357 

414 

10710 

12420 

535 

621 

9175 

11799 

54634 

67254 

71 

tt 

tt 



9 


1.034 

.170 

.175780 

62.5 

440 

13200 

660 

12540 

71338 

71 

tt 




10 


1.066 

.182 

.194012 

62.5 

459 

13770 

688 

13082 

67429 

71 

tt 

tt 



11 


1.004 

.208 

.208832 

62.5 

465 

13950 

697 

13253 

63462 

73 

Cross, 

Hammered 

Plate, 


12 

23.95 

1.006 

.184 

.185104 

73. 

342 

10260 

513 

9747 

52657 





































































103 


TABLE XXXVII. 

•with the exception of the second on bar No. 65, (exp't. 6 of the table,) were made at original sections, 
left by the shears. Specific gravity of 64 and 65.=7.6511 ; and that of 68,70,71 and 73=7.79. 


Weight pro¬ 

ducing tempo¬ 
rary elongat’n. 

Elasticity of 

the bar. 

Length after 

trial. 

Area of the 

section after 

trial. 

REMARKS. 

■< 

f224 
1 336 
1 392 
\ 414 
| 441 
L450 
"224 
| 448 
* 455 

32/ ^ 

31. 

28. 

30. 

32. 

Broke. 

32. 

20. 

Broke. _ 


24.45 

20.9 

C 1.040X.166 7 
1 =.172640 $ 

C .952X.188 7 
1 =.178976 3 

Broke at an original section. 

Do. 


rii2 

1 224 
1 280 
336 
364 
^377 

19.5 - 
16. 

19. 

23. 

26. 

Broke. _ 

► 

24.05 

C 1.008X.192 7 
1 =.193536 3 

f Original section—Broke with the rising motion 
| of the lever while taking up the screw. The 
j friction is therefore to be added. Under a strain 
^ of 280, measured a certain portion and found it 
| 16.7 inches Kng; under 336 lbs. it was 16.9; under 
j 364 lbs. 17.05, and with 377,17.1 inches. Exten- 
Lsion 17.10—16.7=.4 in. or 2.4 per cent. 

j 

1 

rii2 

224 

280 

301 

329 

_336 

38. 

55. 

51.5 

52.5 
46. 

Broke. 


24.3 

C 1.014X.202 7 
l =.204828 3 

Original section. 

1 

^224 

280 

336 

^364 

19. " 

18. 

27. 

Broke. 


24.3 

C 1.012X.188 7 
i =.190256 3 

C Original section.—A portion of this bar, 17.85 
) inches long when under a strain of 336 lbs., was 
7 found to be only 17.817 when the strain was off, 
C.recoil .033=1—540th of the whole length. 

( This was a deeply filed section made for the 
< purpose of ascertaining the weakening effect of 
( the shears. 

r 224 
< 336 
C 357 
r336 
392 
C 414 

20. } 

27. C 
Broke, j 

28. 

26. C 

Broke, j 

24.22 

C .986X.130 7 
l =.128180 3 

C 1.012X-126 7 
l =.127512 3 

C" 1.012X.136 7 
£ =.137632 3 

C 1.056X.156 7 
1 =.164136 3 

t Broke at an unfiled section at the gripe of the 
( wedges. 

Broke again at an unfiled section. 

Do. 

Do. 

( After this exp’t. the bar, which had at first been 
< 24.1 inches long, was found to be 25.3;—gain one 
( and two-tenths by 5 fractures. 

< 

"112 

224 

280 

308 

322 

336 

342 

05.5 -) 
11. 

18. 

19.5 

33. 

24. 

Broke. 



C .960X.160 7 
l =.153600 3 

Broke at an unfiled section. 


9 * 











































104 


TABLE XXXVIII. 


Experiments on bar No. 49. Manufactured from Juniata blooms, 
hammered into boiler plate, by Messrs. H. Blake Co., of Pittsburg, 


Marks. 

_ 

Breadth. 

Thickness" 

Area before 
trial. 

0 

.745 

.205 

.150675 

i 

.744 

.206 

.153264 

2 

.745 

.209 

.155705 

3 

.745 

.211 

.157195 

4 

.747 

.211 

.157617 

5 

.747 

.210 

.156870 

6 

.747 

.210 

.156870 

7 

.748 

.210 

.157080 

8 

.748 

.212 

.158576 

9 

.748 

.211 

.157828 

10 

.746 

.210 

.156660 

11 

.744 

.211 

.156984 

12 

.744 

.211 

.156984 

13 

.745 

.210 

.156450 

14 

.747 

.211 

.157617 

15 

.748 

.212 

.157576 

16 

.745 

.210 

.156450 

17 

.746 

.210 

.156660 

18 

.747 

.211 

.157617 

19 

.742 

.209 

.155078 

20 

.744 

.208 

.154752 

20.3 

.739 

.210 

.155190 

Measures taken alter the 4th 

fracture w ith 343 pounds. 

0 

.725 

.195 

.141375 

1 

.702 

.195 

.136890 

2 

.713 

.197 

.140461 

3 

.730 

.206 

.150380 

4 

.728 

.204 

.148512 

5 

.729 

.204 

.148716 

6 

.726 

.206 

.149556 

7 

.728 

.202 

.147056 

8 

.729 

.202 

.147258 

9 

.725 

.200 

.145000 

10 

.718 

.200 

.143600 

11 

.720 

.200 

.144000 


| Marks. 

Breadth after 

trial. 

Thickness af¬ 

ter trial. 

Area after 

trial. 

Measures after 1st fracture. 

0 

.731 

.200 

.146200 

1 

.724 

.201 

.145524 

2 

.726 

.202 

.146652 

3 

.735 

.208 

.152880 

4 

.732 

.207 

.151524 

5 

.738 

.209 

.154342 

6 

.739 

.206 

.152234 

7 

.740 

.207 

.153180 

8 

.736 

.205 

.150880 

9 

.730 

.203 

.148190 

10 

.726 

.202 

.146652 

11 

.718 

.201 

,144318 

12 

.719 

.203 

.145958 

^Smallest section and 

13> 

.675 

.181|.122175 


dace of first fracture. 

14 

.728 

.201 

.146328 

15 

.734 

.206 

.151204 

16 

.732 

.202 

.147864 

17 

.726 

.201 

.145926 

18 

.722 

.201 

.145122 

19 

.726 

.203 

.147378 

20 

.718 

.200 

.143600 

20.3 

.728 

.199 

.144872 


1 

2 

3 

4 

5 
G 

7 

8 
9 

10 

11 


i 

O u 

* 3 

•A g . 
o £ 

SB'S ** 

<§<2 

‘ 5,0 


.156450 

.156984 

.153264 

.156975 

.156822 

.156450 

.157244 

.157406 

.154971 

.156347 

.157138 


Mean of 11 = .156368 
Mean of 22 orig. meas. = ,156359 


Max, of do. 
Min. oi do. 


.158576 

.150675 


Mean of these two = . 154625 


Difference of the two = .007901 


-e 

d 

£ 

V 

h 


* 

tu0<D 

S — 
•5 cs 

03 W 

£ v 

M'S 


65 

440 

574 

572 

65.75 

65. 

65. 

65. 

65. 

61.5 

61.5 


316 

322 

335 

343 

361 

369 

369 

377 

337 

337 

337 


(C 

4> 


<L 

60 

C3 

U 

<u 

> 

v 


9480 

9660 

10050 

10290 

10830 

11070 

11070 

11310 

10110 

10110 

10110 





















































105 


l 


TABLE XXXVIII. 

Pa. This strip was cut lengthwise of the sheet and then reduced to 
uniformity by filing. Specific gravity , 7.6875. 



c 

e fi 


a 

Qj 

*6 



*3 

pQ 


® 4> 


QJ 

u 



U 

Cfl 

e . 

si 


Qj U 

. 3 

3 r? 

3 P. 

3 

+■* 

QJ 


Friction. 

QJ 

> 

qj 

Sc 

W 

Strength 
er sq. inc' 

DATE. 

t « 

. 

y o 

<3^ 

Effects 
weights ap 

Ci3 
<£ 

2 

a 

..4 

o 

Of 

REMARKS. 



p. 


X> 






1832. 
Nov. 29. 

lbs. 

238 

i no perm. 


Began by trials to ascertain the commence- 





1 elonga. 


ment and progress of elongation. 





245 

(perman. 

( elongat. 







259 

( 20.3hadex- 
# ten, .15 in. 


The length on which measurements were 





266 

.20 


taken was originally 20.3 inches. 





273 

.30 







280 

.36 


After this strain was taken off the bar recoil* 







ed 1-20 inch in length. 





294 

.38 







301 

.58 


Taking: this strain off it recoiled 6-100 inch. 





306 

.95 


On taking off this strain it recoiled 4-100 in- 


• 



313 

1.14 


do. do. 4-100 





316 

1.42 

No, 

The bar of 20.3 inches now measured 21.72. 

474 

9006 

57565 

Dec. 1. 



13 

Broke at the smallest section in the bar. 

483 

9177 

58458 

a 



14 

Part in tin from 5 to 8 inclusive. Fracture 
very near the wedges. 

502 

9548 

62798 

Dec. 6. 



1 

Broke near the wedges ; arrested the mo¬ 
tion before the bar actually parted. 

514 

9776 

62278 

U 



6 i 

Fracture in the tin short and sudden. 

541 

10289 

65609 

U 



m 

Bioke within the wedges. 

553 

10517 

67223 

U 



2* 

Had not been in tin. 

553 

10517 

66883 

u 



9i 

Had been near the tin. 

565 

10745 

68263 

u 



3* 


505 

9605 

61919 

« 



20 

A different piece from the preceding. 

505 

9605 

61434 

Dec. 8. 



18* 

505 

9605 

61121 

U 



17* 

Broke after some delay. 

The mean area of the sections fractured 








was .000009 square inch greater than the 
mean area of the measured points. 








The mean area of the 12 measured points 
from 0 to 11 was, before trial, .156277 ; after 
the first fracture, .149381 ; and after the fourth 
fracture, .145233. Hence the increase of length 
by a strain of 9006 lbs. was 4.4 per cent., and 








by 9776 lbs. it was 7 per cent. 


























106 


TABLE XXXIX. 

Experiments on bar No. 74. Manufactured by H. Blake Co, Pitts-"*] 
burg , from Juniata blooms. Hammered and rolled , making what is ! 
termed hammered plate. This, and numbers 71, 72 and 73, were from \ 
a strip , cut across the sheet. The specific gravity of these four bars was J 


Marks. 

Breadth. 

Thickness. 

Area before trial. 

Wi 

X 

u 

a 

a 

Breadth after trial. 

Thickness after trial. 

Area of section after 
trial. 

DATE. 

No. of the experiment. 

Area of the section of 

fracture before trial. 

Temperature Fahren¬ 

heit. 

Breaking weight in the 

scale. 

Measures after the first frac. 

0 

.770 

.174 

.133980 










1 

.760 

.166 

.126160 

0 

.766 

.173 

.132518 

1833. 





2 

.765 

.165 

.126225 

1 

.759 

.165 

.125235 

Jan. 10, 

1 

.125895 

59.5° 

218 

3 

.762 

.167 

.127254 

2 

.763 

.163 

.125895 






4 

.765 

.167 

.127755 

3 

.759 

.167 

.126753 






5 

.764 

.168 

.128352 

4 

.757 

.167 

.126419 

Jan. 12, 

2 

.119886 

48. 

224 

6 

.761 

.168 

.127848 

5 

.761 

.165 

.125565 






7 

.761 

.166 

.126326 

6 

.758 

. 166 

.125828 






8 

.765 

.165 

.126225 

7 

.746 

.160 

.119360 

tt 

3 

.126442 

48. 

225 

9 

.765 

.166 

.126990 

8 

.750 

.161 

.120750- 






10 

.765 

.165 

.126225 

9 

.755 

.162 

.122310 






11 

.765 

.165 

.126225 

10 

.748 

.161 

.120428 

tt 

4 

.126390 

49.5 

229 

12 

.759 

.164 

.124476 

11 

.736 

.158 

.116288 






13 

.759 

.165 

.125235 

12 

.724 

.154 

.111596 






14 

.763 

.165 

.125895 

13 

.725 

.158 

.114590 

tt 

5 

.126225 

550. 

224 

15 

.765 

.166 

.126990 










16 

.766 

.165 

.126390 

Mean of 14= 

.124129 






17 

.768 

.164 

.125952 










18 

.768 

.163 

.125184 

Mean of the same 14 






19 

.768 

.163 

.125184 

sections 

before trial, 

tt 

6 

.130070 

564. 

266 

19.6 

.754 

.159 

.119886 

.127991 

. Diminution 










.002962 

=2.3 percent. 






Mean of 21 

.125840 





Jan. 19, 

7 

.126607 

52. 

280 

Maximum 

.128352 










Minimum 

.119886 





it 

8 

.126326 

52. 

291 

Mn, of these 2 

.124119 


















tt 

9 

.126568 

52. 

295 

Diff. of the 2 

.008466 


















tt 

10 

.127755 

52. 

295 


Mean of 10 .126216 








































107 


TABLE XXXIX. 


'found to be 7.7910. The bar was two feet in length, of which a section 
, 19.6 inches in length was filed and gauged, and two end sections, about 
j 1 inch wide and 2 inches each in length, were left to be grasped by the 
\jwedges in the first trial. 


Breaking weight multi¬ 
plied by leverage. 

Friction. 

Effective strain. 

Strength in lbs. per 
sq.inch. 

Point of fracture. 

6540 

327 

6213 

49351 

No. 14 

6720 

336 

6384 

53250 

“ 19.6 

6750 

387 

6363 

50332 

near 14^ 

6870 

343 

6527 

51641 

“ 16 

6720 

336 

6384 

50576 

“ 11 

7980 

399 

7581 

58284 

“ 0$ 

8580 

429 

8151 

64380 

“ 8£ 

8730 

436 

8294 

65655 

“ 7 

8850 

442 

8408 

66431 

“ 2j 

8850 

442 

8408 

65813 

“ 4 


REMARKS. 


Stretched very much before breaking. 


Point of frac. not precisely ascertained. 


f Part in tin from 5 to 8 inclusive, 
j Temp, had been as high as 640°. 
\ Broke near the wedges—as far as 
^possible from hot part. 

r Part in tin 4 to 7 incl. Fracture at 
the extremity of the parts included be- 
<( tween the wedges, as far as possible 
from the hot part. Temperature had 
been as high as 602°. 


u 


The mean area of the 10 sections of 
fracture is .000376 sq. inch greater than 
that of the 21 measured sections. 






















108 


TABLE XL. 

Experiments on bars No. 75, 78, 85, 86 and 87. Manufactured at') 
the Juniata Iron Works, near Pittsburg, by Messrs. Schoenberger > 
Son, from blooms , by hammering and rolling. These were all cut off J 


Number of the bar. 

Direction of the slit. 

Number of the experiment. 

DATE. 

Length before trial. 

Breadth. 

Thickness. 

Area of the section of fracture 

before trial. 

Temperature Fahrenheit. 

Breaking weight in the scale. 

Breaking weight X leverage. 

Friction. 

Effective strain. 




1832. 










85 

Length. 

1 

May 10, 

24.5 

1.040 

.260 

.270400 

66 

462 

13860 

693 

13167 

85 

I 

ft 

2 


22.1 

.990 

.254 

.251460 

66 

481 

14430 

721 

13709 

85 

ft 

<■» 

O 



.928 

.250 

.232000 

66 

492 

14760 

738 

14022 

86 

Length. 

4 



.675 

.256 

.172800 

580 

394 

11820 

591 

11229 

86 

«( 

5 



.687 

.256 

.175872 

580 

406 

12180 

609 

11571 

86 

a 

6 



.677 

.257 

.173989 

90 

360 

10800 

540 

10260 

86 

4 C 

7 



.678 

.257 

.174246 

32 

381 

11430 

571 

10859 

86 

4 4 

8 



.715 

.257 

.183755 

32s 

420 

12600 

630 

11970 

87 

Length. 

9 


24.5 

1.028 

.256 

.263168 

66 

464 

13920 

696 

13224 

87 

ft 

10 


19. 

1.060 

.260 

.275600 

66 

506 

15180 

759 

14421 

75 

Length. 

11 


24.6 

.664 

.182 

.120848 

67 

262 

7860 

393 

7467 

75 

(1 

12 


21.4 

.724 

.184 

.125976 

66 

267 

8010 

400 

7610 

75 

if 

13 



.675 

.184 

.124200 

396 

272 

8160 

408 

7752 

75 

if 

14 



.672 

.188 

.126336 

86 

262 

7860 

393 

7467 

78 

Length. 

15 


24.4 

1.028 

.186 

.191208 

73 

280 

8400 

420 

7980 

78 

cc 

16 



1.014 

.186 

.188604 

73 

293 

8790 

293 

8351 


















































































109 


TABLE XL. 

f lengthwise of the sheet and tried either at original or at detached filed 
*< sections. Specific gravity , 7.7580. 


ee 

3 

S' 


■a 

a 

3 

o 

n. 


to 

a 

g . 

C -C 
m ^ 


48694 


54518 


60440 


64983 

65791 

58969 

62360 

65141 


50249 


52326 


61788 

60408 

62415 

59104 


C3 

U 

© 

p. 


bo 

.5 

=3 

P . 

&| 

J= CJ 

he he 

£l 




112 
224 
336 
392 
420 
448 
462 
f224 
| 336 
«< 392 
462 
481 


f224 
336 
*{ 392 

| 441 
L464 


$ 257 
£ 262 
C 168 
£ 267 


41734 


44278 



C3 

-Q 

o 


^2 

W 



21 . ^ 
16. | 
25. y 

25. 

Bro. 


8 . 

Br 

10 . 

Bi 


! - \ 

■o. 5 

'• ? 
ro. 3 



a 

+-> 

to 

P 

QJ 


22.25 


24.7 


24.7 


24.52 


C3 

p 

.© 

o 

CL 

»5 

O 

C3 

<L> 


C 1.036X.240 7 
I =.248640 5 


C . 954 x -240 1 
i =.228960 5 

C .894X-218 ? 
1 =.194892 5 


C 1.028X-184 ^ 
1 =.189888 5 


i 


{ 


1.050X-234 

==.245700 


C .650X-160 7 
£ =.105000 5 


REMARKS. 


1.004X-160 ^ 
=.160640 5 


Broke at an unfiled section. 


Broke at an unfiled section. 


Broke at the filed section. 


r A filed section had been made with 
| an area of 1.012X .256=.259072, 
but the frac. took place at an unfilet 
| sect. Two or three flaws were dis¬ 
closed near the filed section. 

C The filed sect, in this exp. had an 

( area of .270920=1.042 x .260. 


C A short piece only, embraced be 
£ tween the heads. 


Broke outside of oil, near wedges. 
Broke at the filed section. 


r 


< 


A part of this bar, 15.5 in. long, hac 
become 15.55, under a strain of 280 
lbs., but without the tension it was 
15.525. Stretched rapidly, and at 
last broke with a weight of 280 lbs 






















































110 


Methods of Manufacturing Boiler Iron. 

For the information of the general reader who may not be familiar with 
the several processes in the manufacture of iron, referred to in some of the 
preceding, and in several of the subsequent tables, it may be proper here to 
offer a few remarks explanatory of the methods pursued in the United States 
for producing wrought iron of the descriptions embraced in this part of 
the report. 

It has already been stated that the iron furnished to the committee was, 
with a single exception, manufactured by the aid of charcoal. This remark 
applies, of course, to the first process, that of smelting it from the ore, 
which is, for the most part, performed in the usual blast furnaces from 30 to 
40 feet in height, and about 8 feet in their greatest interior diameter, pro¬ 
ducing the different varieties of pig metal. 

It has been mentioned to us, that in Missouri, this process is sometimes 
dispensed with, especially when working the ore of the “ iron mountain,” 
a rich, heavy, magnetic oxide, of a bluish or iron grey colour, and of the 
extraordinary specific gravity of 5.36. The ore is there put into open forge- 
fires resembling the Catalan Forges of the south of Europe, and by a simi¬ 
lar treatment to that which there prevails, brought at once to the condition 
of malleable iron without passing through the state of cast or pig metal. 

The process of manufacturing blooms, or, as they are, when intended for 
boiler plate, technically termed, “ blocks ,” is to subject the pig metal of the 
blast furnace to the combined action of heat and air in an open forge-fire of 
charcoal, drawing off the melted cinder or “slag” by a suitable opening; 
and after stirring and compacting the iron as it begins to agglutinate, or “ come 
round to nature,” to carry the ball to the heavy forge-hammer, and form 
it into a prismatic mass, from 15 to 20 inches in length, and from 5 to 9 
inches in diameter, according to the weight of the plate intended to be ob¬ 
tained from it. These blocks when taken to the rolling mill are heated in an 
air furnace supplied generally with bituminous coal as a fuel, and at the first 
heat are reduced by a heavy hammer into slabs 2 or 3 inches thick, and 
of a length nearly corresponding with that of the blocks. This operation 
discharges much of the remaining cinder, and other impurities left in the 
block by the bloomery treatment. At the second process they go to the rolls 
where they are placed first, with the length of the slab corresponding in di¬ 
rection with that of their axes; secondly, with the length of slab across 
the diameter of the rolls, until it has been increased to the required breadth 
of the finished sheet; and finally, by placing the original length of slab 
once more parallel to the axes, and extending the plate till it has been re¬ 
duced to the requisite thickness. 

Sheet iron by the process of puddling, is, for some purposes, manufac¬ 
tured from pig metal into malleable iron, without the intervention of any 
other process of refining, than that which takes place in the puddling fur¬ 
nace itself. But for boiler plate, it is believed to be customary, first to sub¬ 
ject it to the action of the “ run-out” refinery fire, in an open charcoal, or coke 
furnace urged by a powerful blast. As, in this fire, a large mass of metal is 
melted down at a time, and the cinder drawn off separately, the earthy impuri¬ 
ties which in simple puddling would be retained in the balls, are at once remo¬ 
ved, and by the aid of a small stream of water which is occasionally made to 
accompany the blast, a partial decarbonization of the metal is probably effect¬ 
ed. When in full fusion, the metal is drawn off or “ run out” into an 
oblong bed, and while still hot, is broken up into blocks of a few pounds 
weight each, to be conveyed to the puddling furnace. In the latter it under- 


Ill 


goes a second fusion, and the usual operations till agglutinated into 
“ balls.” Bituminous coal is the fuel here employed, and the furnace is of 
the reverberatory form. The balls pass from this furnace first to the large 
hammer, by which they are moderately compacted; and immediately after to 
the rolls, by which they are reduced into broad bars or slabs. The latter are 
reheated and at once rolled into plate, the former cut up into lengths of about 
15 or 18 inches and piled, three high, to be reheated and welded into slabs of 
sufficient magnitude for plates of boiler iron. 

Piled iron , when manufactured from blooms , does not, generally, it is 
believed, undergo a second hammering after being received at the rolling 
mill. At the first heat it is reduced to bars an inch or more in thickness, 
when it is cut up, piled as before mentioned, and rolled into plate. 

The practice of piling appears to be followed, in some instances, from a 
supposition that a greater security from flaws and other blemishes, must re¬ 
sult from combining the strength of three distinct laminae—and fortifying 
the weak points of one by the strong parts of the two others, than could pro¬ 
bably be derived from the simple unlaminated sheet, in which any imperfec¬ 
tion would, it is supposed, extend through the entire thickness.—But the 
uncertainty of uniform welding between the members of a pile is sufficient 
to warrant some hesitation in approving this method. Table XXXIII., at expe¬ 
riments 12 and 13, affords evidence that the structure of this description of 
boiler iron is sometimes exceedingly imperfect, owing to a want of com¬ 
plete welding between the laminae of which it is composed. 

In a subsequent part of this report, will be found discussions on the 
relative influence of the different processes above described, and also on the 
repetitions of piling upon tenacity. It will there be seen that the practice of 
piling or faggoting may not in all cases prove detrimental to the iron, but 
will depend in some measure upon the degree of refining which it has pre¬ 
viously undergone,—-and its consequent freedom from earthy or other 
impurities which might interfere with accurate welding, as well as upon 
the temperature employed for that process. If, after reducing either refinery 
blooms or puddled balls to thin bars, fit for piling, there be made a perfect 
union of surfaces during this operation, the latter has evidently the advantage 
of affording to the impurities a more ready escape from interior portions of 
the metal, than would otherwise be obtained. 


10 


112 

TABLE XLI. 


Experiments on bars No. 81, 83, 84, SO and 91. Manufactured at the Juniata Iron Works , near Pitts - ) 
burg , by Messrs. Schoenberger £r Son, from blooms by hammering and rolling. These strips were all cut J 


No. of the bar. 

Direction of 

the slit. 

A 

C- 

X 

V 

o 

o 

fc 

DATE. 

Length be¬ 

fore trial. 

! 

Breadth. 

Thickness. 

Area of the 

section of frac¬ 

ture before tri¬ 
al. 

Temp. Fah. 

Breaking wt. 

in the scale. 

Br. wht. X 

leverage. 

Friction. 

Effective 

strain. 

Strength in 

pounds per sq. 

inch. 

! 81 

Cross. 

1 

1832. 
April 7. 

24.075 

.500 

.186 

.093000 

o 

65 

140 

4200 

210 

3990 

42904 

181 

<i 

2 



.444 

.182 

.080808 

65 

133 

3990 

199 

3791 

46914 

81 

a 

3 



.440 

.186 

.081840 

65 

150 

4500 

225 

4275 

52236 

I 1 

ii 

4 



.490 

.184 

.090160 

65 

200 

6000 

300 

5700 

63221 

83 

Cross. 

5 


24.0 

1.014 

.182 

.184548 

65 

273 

8190 

409 

7781 

i 

42162 

83 

<< 

6 



.936 

.184 

.172224 

65 

296 

8880 

444 

8436 

48983 

83 

ii 

7 



.988 

.180 

.177840 

66 

353 

10590 

529 

10061 

56573 

84 

Cross. 

8 


23.8 

1.060 

.182 

.192920 

66 

289 

8670 

433 

8237 

42696 

84 

tt 

9 


9.00 

1.084 

.182 

.197288 

66 

319 

9570 

478 

9092 

46085 

84 

ii 

10 


15.2 

.990 

.178 

.176220 

66 

294 

8820 

441 

8379 

47548 

90 

Cross. 

11 

April 14. 


.533 

.247 

.131651 

600 

263 

7890 

394 

7496 

56938 

90 

ii 

12 



.679 

.245 

.166355 

54 

263 

7890 

394 

7496 

45060 

90 

a 

13 



.674 

.252 

.169848 

54 

328 

9840 

492 

9348 

55037 

90 

a 

14 



.608 

.240 

.145920 

54 

295 

8850 

442 

8408 

57620 

90 

n 

15 



.610 

.245 

.149450 

50 

« 

270 

8100 

405 

7695 

51489 

90 

a 

16 



.585 

.250 

.146250 

596 

296 

8880 

444 

8436 

57682 

91 

Cross. 

17 


24. 

1.072 

.246 

.263712 

65 

392 

11760 

588 

11172 

42365 
























































































113 


TABLE XLI. 

off crosswise of the sheet, and tried either at original or at detached filed sections. 
7.7 580« 


Specific gravity 


O O 

*£ a 

• 91 a 
_ o 

£ a 

o u 


S 

^3 

o 

u * 
04 £ 


on 


C 112 
£ 140 


C 224 
£ 273 



o 


s* 

W <u 

A 


u 

a 

a i 

A 

9 

££ 

C . 

t-).S 


36.5' 

Broke 


3 


34. 

Broke 


\ 


10 . 


Broke. ^ 



224 

317 

319 




33. 

24. 

Broke. 


53. -) 
Broke. 5 


24.05 


9.2 


fll2 

0.50.5'-] 

224 

1.16. 

. 280 

1.00. 

i 347 

0.34. 

364 

0.20.5 

1392 

Broke.^ 


> 


24.15 


Area after 

trial. 

REMARKS. 

C -500X.182 l 
£ =.09iooo 5 

This was a narrow strip and broke at 
an original section. 

do. do. 

do. do. 

do. do. 

C1.014X-162 ^ 
£ =.174408 5 

C .932X-162 l 
£ =.150984 5 

C .988X-168 1 
£ =.157034 5 

f The weight recorded was added by 
7 lbs. at a time, not supposing the 
breaking weight to be nearly attain- 
<( ed. The bar had borne 266 lbs. 

| without signs of yielding. A filed 
j section had been made .928 inch in 
l_breadth, and .180 thick, area 167040. 

Broke at an original section. 

f The filed section had now been re- 
| duced to .904 X* 1^0=. 153680. The 
J section filed in the first experiment 
' now bore 60231 lbs. per sq. inch 
without breaking, and calculating on 
IJts present area it bore 65467. 

1.046X-162 
=.169452 

1.020X-160 

=.163200 

. 974 X- 160 
=.155840 

C A filed sect, in this bar had an area of 
,896xd76=,157696. Brokeat an ori- 
Lginal sect, in the middle of the bar. 

C A filed section in the part now under 
J trial has the dimensions .884x*178= 
j .157352. Its strength as indicated by 
L_this trial was above 50421 lbs. 
f A section had been filed with the di- 
J men..884 x* 178=.157352, and giving 
] a strength above 56046. Broke at an 
^original section near the wedges. 


r Temp, not very accurately noted at 

< the instant of fract., believed to have 
L been as high as numb, recorded. (600.) 

C Broke at a filed section. 

£ The filed sect, not so deep as before. 
The filing still less than the preceding. 

C Much deeper filing than either of the 
£ two preceding. 

r The w’ht. is approximate only, as the 

< bar broke instantly on applying 270 
Libs; which was supposed its full load. 

Broke in tin at the filed section. 


Broke at a section not filed. 

• 





















































114 


TABLE XLI1. 

Experiments on bar No. 88. Manufactured at the Juniata Iron~\ 
Works, near Pittsburg, by Messrs. Sclioenberger fy Son, from blooms, [ 
by hammering and rolling into boiler-plate. This strip cut of \ 
lengthwise of the sheet, and tried after having been reduced to a nearly J 


Marks. 

Breadth. 

Thickness. 

■ 

Area before trial. 

Marks. 

Breadth. 

Thickness. 

Area after trial. 

After the 2d fracture, 321 lbs. 

0 

.741 

.219 

.162279 

0 

.635 

.130 

.082550 

1 

.767 

.219 

.1 67973 

1 

.752 

.205 

.154160 

2 

.767 

.222 

.170274 

2 

.756 

.213 

.161028 

3 

.767 

.223 

.171041 

3 

.769 

.216 

.166104 

4 

.766 

.220 

.168520 

4 

.767 

.217 

.166439 

5 

.767 

.221 

.169507 

5 

.768 

.219 

.168192 

6 

.764 

.221 

.168844 

6 

.759 

.221 

.167739 

7 

.771 

.220 

.169620 

7 

.762 

.220 

.167640 

8 

.768 

.219 

.168192 

8 

.750 

.213 

.159750 

9 

.769 

.220 

.169180 

9 

.759 

.214 

.162426 

10 

.767 

.222 

.170274 

10 

.755 

.215 

.162325 

11 

.765 

.222 

.169830 

11 

.758 

.215 

.162970 

12 

.769 

.223 

.171487 

12 

.763 

.220 

.167860 

13 

.769 

.221 

.169949 

13 

.761 

.215 

.163615 

14 

.770 

.218 

.167860 

14 

.761 

.213 

.162093 

15 

.769 

.221 

.169949 

15 

.763 

.217 

.165571 

16 

.768 

.222 

.170496 

16 

.761 

.215 

.163615 

17 

.771 

.221 

.170391 

After the fith fracture, 370 lbs. 

18 

.767 

.220 

.168740 





19 

.767 

.221 

.169507 

3 

.755 

.212 

.160060 

20 

.780 

.228 

.177840 

4 

.743 

.204 

.151572 





5 

.752 

.212 

.159424 

Mean of 21 

.169611 

6 

.745 

.213 

.158685 





7 

.753 

.214 

.160542 


Maximum 

.177840 

8 

.749 

.210 

.157290 


Minimum 

.162279 

9 

.746 

.211 

.157406 





10 

.742 

.208 

.154336 

Mn. of these 2 

.170059 









The part from three 

DifF. of the 2 .015561 

to ten was, at 

the time 





of these measurements. 





7.51 inches in 

length. 


DATE. 


1832. 
Dec. 22, 


U 


Dec. 29, 


1833. 
Jan. 3, 


U 


u 


6 

7 

8 
9 

10 


Cm 

O 


.2 c* 

8J 

X v 

a 

«-* ZJ 
Cm “ 
O V 

s ^ 

< a 


.170391 

.162912 

.169949 

.167860 

.170658 

.170052 

.170657 

.168521 

.168520 

.169103 

.169507 


11 

Mean of 11 sections .168921 


3* 

Pm 


cs 

c 


610° 

630 

55 

55 

55 

55 

61 

61 

61 

61 

61 


























































115 


TABLE XLII. 


f *uniform size by filing , and gauged at every inch , from 0 to 20. 
J Specific gravity , 7.7922. Original size before filing about 1 tnc/t 
j 5?/ .25. 


Breaking weight in 
the scale. 

_ _ i 

Breaking weight X 
leverage. 

Friction. 

Effective strain. 

Strength in lbs. per 

square inch. 


Points of fracture. 

REMARKS. 








r Had been, during the experiment, 

296 

8880 

444 

8436 

49509 

No. 17 

< for a short time as high as 630°. 
C. Part in tin from 11^ to 15|. 

321 

9630 

481 

9149 

56159 

U 

9 £ 

Part in tin from 4 to 8. 

346 

10380 

519 

9861 

58024 

U 

15 


353 

10590 

529 

10061 

59937 

u 

14 


358 

10740 

537 

10203 

59786 

u 

Hi 


370 

11100 

555 

10545 

62010 

u 

m 

C Slightly griped by the wedges at 
the section of fracture. 

368 

11040 

552 

10488 

61457 

u 

n 

Do. 

385 

11550 

577 

10973 

65113 

u 



385 

11550 

577 

10973 

65114 

u 

4 


383 

11490 

574 

10916 

64552 

u 


C Part broken olf in the first ex- 

320 

9600 

480 

9120 

53803 

u 

19 

periment. 

The mean area of the 11 sections 
of fracture is .000690 sq. inch less 
than the mean area of the 21 mea¬ 
sured sections. 


10 * 























of bar 


116 

TABLE XLIII. 

Experiments on bars No. 94,95,107,108, 111, 112,114 and 120, cut from plates of boiler iron, manufactured 


a 

'£ 

• r* 

O V 

z-2 


94 


G G 
©•" . 
•s.n 
S <" 

U 0) 

Q'S' 

© 


to 


w u 
3 « 


L’gth. 


u 


u 


u 


u 


No. of exp. 

DATE. 

Length ot 

the bar be¬ 

fore trial. 

! . 

Breadth. 

Thickness. 

Area before 

trial of the 

section of 

fracture. 

G5 

cs 

G. 

£ 

il 

H 

Breaking 

weight in 

the scale. 

Br. wt. X 

leverage. 

1 Friction. 

Effective 

strain. 

i 

1832. 
April 21, 

24.07 

1.074 

.252 

.270648 

68.° 

511 

15330 

766 

14564 

2 

u 


1.083 

.252 

.272916 

70.75 

550 

16500 

825 

15675 

3 

«« 


1.060 

.252 

.267120 

70.5 

560 

16800 

840 

15960 

4 

a 


1.083 

.252 

.272916 

73.75 

574 

17220 

861 

16359 

5 

a 


1.062 

.252 

.267524 

70.75 

581 

17430 

871 

16559 

6 

April 25, 

24.10 

1.006 

.238 

.239428 

62.25 

382 

11460 

573 

10887 

7 

June 10, 


1.040 

.241 

.250640 

79.5 

431 

12930 

646 

12284 

8 

<t 


1.060 

.210 

.222600 

79.5 

448 

13440 

672 

12768 

9 

u 


.792 

.236 

.186912 

79.5 

341 

10230 

511 

9719 

10 

66 


1.046 

.237 

.247902 

79.5 

493 

14790 

739 

14051 

11 



1.035 

.072 

.074520 

70.75 

145 

4350 

217 

4133 

12 



.985 

.078 

.076830 

70.75 

151 

4530 

226 

4304 

13 



1.083 

.078 

.084474 

70.75 

169 

5070 

253 

4817 

14 


21.6 

1.130 

.076 

.085880 

62. 

115.5 

3465 

173 

3292 

15 


22.4 

1.046 

.146 

.152716 

62. 

225 

6750 

337 

6413 

16 


21.7 

1.050 

.136 

.142800 

62. 

205.5 

6165 

308 

5857 

17 



.914 

.240 

.219360 

62. 

469.4 

14082 

704 

13378 

18 


22.8 

.980 

.272 

.266560 

62. 

430.5 

12915 

645 

12270 


95 


Cross. 


u 


u 


(t 


u 


107 


Cross. 


a 


46 


46 


108 


111 


112 


Uncer. 


66 


66 


114 


120 


46 









































































117 

TABLE XLIII. 


by R. Lukens, Chester Co. Pa. The sect's of frac. were those oj the bars as they came from the shears. 


Strength in 
pounds per 
squareinch. 

Weights 

producing 

elongation. 

Elasticity 
of the bar. 

Length af¬ 

ter trial. 

Area after 

trial. 

REMARKS. 


T224 

37'1 






280 

45 






336 

38 




t 

53811 

<( 392 

36 

> 





448 

25 





483 

25 






L511 

Broke._j 



( 1.068X.212 7 
l =.226416 $ 

Broke within the wedges. 

57435 





Area after fracture 83 per cent, 
of the area before trial. 

59748 





C .989X-201 7 
l =.198789 5 

C .994X.1907 
( =.188860 3 

Area after fracture, 70 per cent. 
This fracture developed a remark- 

59941 





ably clear and compact structure. 
Area 69 per cent. 

61897 





C . 990X-223 7 

1 =.220770 5 

Area after fracture, 82 per cent. 


T224 

34' 



C .970X.214 7 
l =.207580 3 


45471 

< 336 
(.382 

26 

Broke,. 


24.19 

Area after fracture, 87 per cent. 

48994 




C .973 X.200 7 
1 =.194600 3 

Area after fracture, 77 per cent. 






C 1.030X-208 7 

Broke at an original section. Area 

55184 





l =.214240 3 

after fracture .96 per cent. 

51998 





C .765X*213 7 
l =.162945 3 

Area after fracture, 87 per cent. 

56680 





C 1.050X.209 l 
l =.219450 3 

Area after fracture, 89 per cent. 







f Broke at an original section ; a 







filed section had been made = 







.985X-978=.077830, which tho’ 
smaller in one direction was great¬ 
er in the other, and of greater 

55461 





^ 1.035x*0/0 7 
( =.072450 3 






( .954X 066 7 
l =.062964 3 

area than the section of fracture. 

1 Area after fracture, 97 per cent. 

56020 





Area after fracture, 70 per cent. 

57035 





C 1.083X-061 7 
l =.066063 3 

Area after fracture, 78 per cent. 

38332 



22.6 

C1.030X-062 7 
l =.063860 5 

Area after fracture, 74 per cent. 

41926 



22.8 

C .994X.HO l 
l =.109340 3 

-- 

Area after fracture, 71 per cent. 

41015 



22.5 



60986 






46031 



23.5 


The mean area of the sections of 
fracture after trial is 80.7 per cent, 
of the mean area of the same sec¬ 
tions before trial. 

1 


















































































118 


TABLE XLIV. 


Experiments on bars No. 125, 130, 133, 135 and 137. Manufactured by Messrs. S. E. H. & P. Ellicott, ) 
of Baltimore . The ore obtained on the Patapsco , 8 miles from Balt., reduced at Elkridge furnace, and ^ 
forged at Patuxent forge, in the neighbourhood of that city. A slab was drawn out under the ham- ) 


No. of the 
bar. 

Direction 
of the slit. 

No. of exp. 

DATE. 

1 Length be¬ 

fore trial. 

Breadth. 

Thickness. 

Area of 

section be¬ 

fore trial. 

Tempera¬ 

ture Fah. 

Br. weight 

in the scale. 

Br. weight 

X leverage. 

Friction. 

Effective 

strain. 




1832. 










125 

L’gth, 

1 

June 13. 


1.060 

.150 

.159000 

394.° 

319 

9570 

478 

9092 

125 

ii 

2 

u 


.982 

.154 

.151228 

394. 

336 

10080 

504 

9576 

125 

it 

3 

ii 


.982 

.154 

.151228 

82. 

350 

10500 

525 

9975 

130 

Cross. 

4 


16.6 

1.052 

.248 

.260896 

60. 

529 

15870 

793 

15077 

133 

Cross. 

5 

June 20. 


1.003 

.130 

.130390 

214. 

259 

7770 

388 

7382 

133 

it 

6 

ii 


.900 

.137 

.123300 

214. 

265 

7950 

397 

7553 

133 

it 

7 

a 


1.022 

.140 

.143080 

394. 

284 

8520 

426 

8094 

133 

it 

8 

a 


.817 

.150 

.122550 

74. 

300 

9000 

450 

8550 

133 

it 

9 

it 


.890 

.165 

.146850 

74. 

274 

8220 

411 

7809 

135 

Diag. 

10 



.462 

.247 

.114114 

78. 

249 

8470 

423 

8047 

135 

it 

11 


24. 

1.020 

.247 

.251940 

84. 

422 

12666 

633 

12027 

135 

it 

12 



1.012 

.247 

.249964 

84. 

442 

13260 

663 

12597 

135 

it 

13 



1.012 

.247 

.249964 

84. 

451 

13530 

676 

12854 

135 

ii 

14 



1.012 

.247 

.249964 

84. 

451 

13530 

676 

12854 

137 

Diag. 

15 

June 13. 


1.040 

.271 

.281840 

79.5 

498 

14940 

747 

14193 

137 

ii 

16 

ii 


.950 

.248 

.235600 

80. 

469 

14070 

703 

13367 

137 

it 

17 

ii 


.972 

.262 

.254664 

212. 

529 

15870 

793 

15077 

137 

ii 

18 

ii 


.850 

.254 

.215900 

212. 

515 

15450 

772 

14678 


























































































119 


TABLE XLIV. 


mer andcut in three different ways, viz. 125 longitudinally with the grain; 120 and 133 transversely, and 
1J5 ana 137 diagonally. The pieces thus cut off, subsequently drawn with the small hammer to nearly 
the size indicated in the column of areas. In some instances, reduced by fling at particular sections. 


x $■" 

■w Qj 

tea, . 

i i i 

X ft 

cJL 

cs 

■Sort 


s A 

<V • o 
u* z, 

CO — 

s; 5T 

*-> 

A 

- s ft 3 
£ 3 g-5 
3 O 0S 

zj a 

4-» —' 

3 « 

5 *■* - 

” tM 

X — 
So-2 

s a 

u , 

& 

Cm 0J -J 

O jj — 

rt o 2 Z 

1 y cc ^ 

<, ai 

REMARKS. 

• V) 

■3 C, SuO 

O 

+-> 

c/5 Cm w 


57182 

63322 




C.892X-091 7 
1 =.081172 5 

Broke out of the oil—near the wedges. 

C Do. do. Calculating on the filed sec- 
j tion, we find it bore the w’ght per in. here 
<{ noted. As the actual section of fracture 






| was not gauged before trial, we cannot de- 
Lterxnine precisely the str’gth at that point. 

65960 




^ .840x*089 7 
7 =.074760 3 

Broke at the filed section. 


r 56 

08/ ^ 

16.6 




112 

168 

08.5 

09. 

16.6 




224 

11 . 

16.6 



57789 

280 

336 

436 

13.5 

12 . > 
16. 


C . 952 X -210 7 
7 =.199920 3 

t The elasticity under a weig'ht of 336 lbs. 

< in the scale, was taken after the weight 
( had been suspended 15 hours. 


466 

12 . 

16.725 




485 

16. 





506 

24. 

16.975 




L529 

Broke. ^ 

17.13 



56614 




9.893X-091 7 

Broke outside of the oil at a filed section 




1 =.081203 3 

not the smallest. 

61168 




5-.775x.090 7 

Broke in oil at filed section. 




7 =.069750 3 
C.921x-100 7 

Broke out of the filed section at a thick 

56570 




7 =.092100 3 

part of the bar. 

69767 




C. 723x-100 7 

Broke at filed section. 




7 =.072300 3 

C .728x -104 7 
7 =.075712 3 

Broke at a. filed section. 

53176 





5 .368X-153 7 
7 =.056304 3 

f The strength deduced, is that of the 

70517 




J smallest filed section. The section actually 
j fractured, was .510 X.247=.125970 giving a 
^strength of 63880 lbs. 

47738 




5-.790x.150 7 

Before this fracture the bar had been 




7 =.118400 5 

extended 1,9 inches. 

50039 




5.787X-160 7 

The whole bar had now become irregu- 




7 =.125920 3 

lar with alternate large and small sections. 

51423 




5.825X-168 > 

No stretching except very near the 




7 =.138600 3 

section of fracture. 

51423 




5 " .800x * 1^8 ? 

7 =.142400 3 

Point of fracture obs'd to be very warm. 

50358 

5 490 

44/ £ 


5 .802x > 176 7 

Original section, as hammered. 

7 498 

Broke. 5 


7 =.141152 3 

56736 

C336 
< 420 
C.469 

20 . 

40. i 

Broke, j 


5.772x-158 7 
7 =.121996 3 

Filed section. 




Heated in oil to 212°. Broke outside of 

59203 





the oil, near the wedges. 

67939 




C.745X.170 7 

7 =.126650 5 

Broke in the oil at the filed section. 

The mean area of the 16 sections after 






fracture is 55.6 per cent, of the correspond¬ 
ing areas before trial. 































































120 


TABLE XLY. 

Experiments on bars No. 148, 151, 167 and 169. Manufactured by"j 
S. E. H. P. Ellicott. The ore obtained on the Patapsco , Smiles from t 
Baltimore. Rolled in the usual manner into boiler plate , and these strips J 


No. of the bar. 

Direction of the slit. 

No. of the experiment. 

DATE. 

Length of the bar be¬ 
fore trial. 

Breadth. 

Thickness. 

Area of the section 

before trial. 

Temperature, Fah. 

Breaking weight in 

the scale. 

Breaking weight X 

leverage. 

Friction. 

Effective strain. 

Strength in pounds 

per square inch. 

148 

Cross. 

1 

1832. 
May 2, 


1.006 

.250 

.251500 

64° 

463 

13890 

694 

13196 

52468 

148 

ft 

2 

ti 

20.6 

.994 

.250 

.248500 

64 

476 

14280 

714 

13566 

54591 

148 

tt 

3 

ti 


.755 

.243 

.183465 

394 

449 

13470 

673 

13797 

69752 

148 

it 

4 

tt 


.690 

.253 

.174570 

81 

399 

11970 

598 

11372 

65143 

151 

Cross. 

5 

tt 

30,5 

1.008 

.250 

.252000 

64 

476 

14280 

714 

13566 

53811 

151 

it 

6 

it 

29.8 

1.016 

.250 

.254000 

64 

489 

14670 

733 

13937 

54868 

151 

it 

7 

it 


.958 

.248 

.237584 

64 

503 

15090 

754 

14336 

60344 

151 

ii 

8 

tt 


1.036 

.250 

.259000 

64 

503 

15090 

754 

14336 

54820 

151 

tt 

9 

tt 


1.008 

.248 

.249984 

64 

504 

15120 

756 

14364 

57459 

167 

Cross. 

io 

May 9, 

30.4 

.942 

.160 

.150720 

69 

292 

8760 

438 

8322 

55222 

167 

tt 

11 

ii 

27.2 

1.004 

,156 

.156624 

69 

296 

8880 

444 

8436 

53862 

167 

ti 

12 

ii 

19.33 

.992 

.156 

.154752 

69 

307 

9210 

460 

8750 

56539 

169 

Cross. 

13 

i i 

30.1 

1.032 

.132 

.136224 

69 

240 

7200 

360 

6840 

50212 

169 

i i 

14 

it 


1.032 

.132 

.136224 

69 

240 

7200 

360 

6840 

50212 

169 

it 

15 

ti 


1.032 

.132 

.136224 

69 

240 

7200 

360 

6840 

50212 

169 

tt 

16 

if 


1.000 

.132 

.132000 

69 

240 

7^00 

360 

6840 

51818 

169 

tt 

17 

<t 


1.000 

.132 

.132000 

69 

254 

7620 

381 

7239 

54841 

169 

ii 

18 



1.020 

.132 

.134640 

69 

277 

8310 

415 

7895 

58839 





































121 


TABLE XLV. 

'cut off with the shears across the direction of rolling. Reduced by 
fling from about one inch in breadth , in some of the experiments to the 
sections recorded; mothers the bars left as they came from the shears. 


& 

tp 

w 

3 

•D 

O 

04 
« • 

5 C5 

U2 

V CS 

o 

Elasticity of the bar. 

Length after trial. 

Area of the seetion af¬ 

ter fracture. 

REMARKS. 

f212 
| 336 
392 
) 448 
L463 

C 463 
( 476 

29'"') 
33 | 

42 y 

45 f 
Broke. J 

37'7 
Broke. 5 

20.9 

.248000 

.205792 

Fracture at an original section. 

Broke at the smallest section, fracture compound. 

Broke suddenly at the filed section, but not by any 
sudden addition of weights. 

Broke at the filed section, a fair experiment. 

f224 
J 336 
} 448 
L476 
476 
489 

30'^ 
33 l 
40 r 
Broke. J 
36'7 
Broke. 5 

30.9 

.225096 

.224200 

.185120 

.208320 

.220000 

A filed section was made near one end of the bar 
but the fracture took place near the other end. 

Broke partly within the wedges. 

Broke at the fled section. The four other sections 
show 8.4 per cent, less strength on an average than 
this. 

Broke at an unfiled section. 

Do. do. 

f224 
) 266 
) 284 
L292 

306 

307 

38'^ 
36 l 
42 f 
Broke. J 

29'7 
Broke. 3 

31.1 

27.33 

19.4 

.097812 

.114228 

.112840 

Section filed in the breadth, fracture much warmer 
than the hand at the moment of breaking. 

Original section, fracture warm. 

Broke at the smallest section. 

C 253 
(254 

44'7 
Broke. 5 


.096200 

.116560 

.121088 

.095800 

.112632 

.125748 

Broke at two places at a distance from each other. 
All the fractures on this bar were made at original 
or unfiled sections. 

Two fractures occurred simultaneously near each 
other. 

The whole bar has now been extended from 30.1 
to 31.3 inches by these six fractures. The number 
of points actually separated was 8, two fractures 
having twice occured at the same moment. 




























122 


TABLE XLVI. 


Experiments on bars No 154, 157,171 and 174, and Nos. 142 and 143. Manufactured by Messrs. S. E. I 
H. ir P. Ellicott. The ore obtained on the Patapsco, 8 miles from Baltimore, rolled into boiler-plate > 
in the usual manner . The first, four strips cut off diagonally, and the last two longitudinally with the ) 


No. of the 
bar. 

Direction 
of the slit. 

p- 

X 

V 

o 

c 

-fc 

DATE. 

Length be¬ 

fore trial. 

Breadth. 

Thickness. 

Area be¬ 

fore trial. 

1 

Tempera¬ 

ture, Fah. 

«_> • 

^ (Lr 

•r o 

cr 
£ Qj 

. A 
u 

Br. weight 

X leverage. 

1 

i 

! Friction, 

1 

Effective 

strain. 

Strength in 

lbs. per sq. 

inch. 

154 

Diag. 

1 

1832. 
May 5. 

30.4 

.952 

.250 

.238000 

60.° 

427 

12810 

640 

12170 

51134 

154 

U 

2 

it 

23.08 

.960 

.250 

.240000 

60. 

438 

13140 

657 

12483 

52012 

154 

u 

3 

<« 


.900 

.250 

.225000 

60. 

464 

13920 

696 

13224 

58773 

157 

Diag. 

4 

(i 

30.35 

1.024 

.250 

.256000 

62. 

468 

14040 

702 

13338 

52102 

157 

it 

5 

ti 


1.000 

.250 

.250000 

66.5 

469 

14070 

703 

13367 

53468 

171 

Diag. 

6 

May 12. 

30.2 

.960 

.134 

.128640 

69. 

251 

7530 

37 6 

7154 

55612 

174 

Diag. 

7 

it 

30.2 

.896 

.132 

.118272 

69. 

235 

7050 

352 

6698 

56632 

174 

U 

8 

it 

27.7 

.972 

.134 

.130248 

69. 

235 

7050 

352 

6698 

51425 

174 

U 

9 

Mayl9 

23.9 

.974 

.134 

.130516 

69. 

246 

7380 

369 

7011 

53717 

174 

u 

10 

<( 

22.1 

.956 

.136 

.130016 

69. 

246 

7380 

369 

7011 

53924 

142 

L'gth. 

11 

Ap.18. 

30.4 

1.110 

.240 

.266400 

62. 

415 

12450 

622 

11828 

44399 

143 

L’gth. 

12 

Ap.25. 

30.6 

1.000 

.236 

.236000 

62. 

440 

13200 

660 

12540 

53135 

143 

u 

13 

it 

29.3 

1.034 

.236 

.244024 

62. 

478 

14340 

717 

13623 

55826 

143 

it 

14 

it 


.944 

.238 

.224672 

62. 

478 

14340 

717 

13623 

60635 

143 

• 

u 

15 

May 2. 


1.014 

.236 

.239304 

64. 

495 

14850 

742 

14108 

/ 

58954 







































































































123 


TABLE XLVI. 

sheets. Tried either at original sections, or at points more or less reduced by filing from the breadth 
a semicircular cavity on each edge. The bars originally cut one inch tvide. 


2 5c 


• 

" = t£ 
•" 2 § 
rs v 


C 224 
| 336 
<< 392 
I 420 
1427 

C 392 
£ 438 

f 434 
J 449 
] 459 
L464 


f224 
336 
| 392 
J 420 
^ 438 
448 
462 
468 


f 224 
\ 251 


u 
v a 

a c 

© 


>£-> A 

t-' z, 

fcjo ^ 


30 J 
30. 

38. 

42. 

Broke. 

21 . 

Broke. 

22 . 

25. 

26.5 

Broke. 


27. 

50. 

50. 

51. 

49. 

45. 

46.5 

Broke. 


18. 

Broke. 


44.5 

50.5 
Broke. 
1.05 
Broke. 
41. 

44. 

Broke. 

39. 

Broke. 


f224 
280 
336 
, 370 
< 392 
435 
440 
440 


08.5 

14. 

15. 

27. 

26.5 
32. 

31.5 
Broke. 


30. 

33. 

48. 

53. 

52. 

44. 

47. 

Broke. 


t 464 41 
j 478 Broke. 


r 485 
> 485 
A 495 
(j95 


37.5 

33.5 

36.5 
Broke. 


>>30.52 


J 


31.0 


a 


Ci c3 

^ -r* 


REMARKS. 


.215740 

.212676 

.189200 


.994X-212? 
=.210728 S 


30.5 


| 30.7 
27.9 
24.1 
22.3 


.962X-122? 
=.117364 5 


Did not break at the smallest section. 


Do. 


Broke near the smallest section. 


p A section was filed in the breadth of the bar 
| so as to leave an area of ,962X.25=.240500 of a 
1 sq. inch ; while the smallest original section was 
j 1.015X.248=.251968, and the section actually 
broken was .256000. Calculating on the filed 
| section we obtain a strength of more than 
j 55459, because the bar was not broken at that 
Lpoint. 

This on the same filed section shows a strength 
a little above that calculated in the preceding 
remark. 


.796X-102 7 
l =.081192 5 
^ .950X-120? 
I =.114000 5 
.950X-114? 
I =.108300 $ 
C .934X-H6? 

I =.108344 5 


31.1 


31.3 


i 


1.09X-230 I 
=.250700 5 


.994X-1862 
=.184884 3 
.800X-152? 
=.121600 $ 


.990X-214 7 
=.211860 5 


Broke in the middle of the bar. 


Filed.—Broke at the filed section. 


Do. 

Do. 

Do. 


do. 

do. 

do. 


Original section. 


r Did not break at the smallest section. After 
3 the elasticity had been taken under 440 lbs. the 
(.slime weight broke the bar. 


f Did not break at the filed section, though its 
^area was only .944X.238=.224672. 

C Br. at the filed section noted in the preceding 
\ remark. 

r The elasticity may he very slightly erroneous, 
I as the index rose a little way above the top of the 
| scale. When the bar appeared to be giving way 
i under 494 lbs., 9 lbs. were taken off, so as to leave 
i 485, with which the elasticity was again tried, 
and found to be 33.6'. Having restored the 
| 9 lbs. the elasticity was again tried, and found 
l 34.5 / for the whole weight. 


11 






























































124 


TABLE XLYII. 


Experiments on bars No. 160, 162, and 164. Manufactured byl 
S. E. H. 8c P. Ellicott. The ore was obtained on the Patapsco , 8 v 
miles from Baltimore , rolled into boiler plate in the usual manner ,J 


No. of the bar. 

Direction of the slit. 

No. of the experiment. 

DATE. 

Length of the speci¬ 
men before trial. 

Breadth of the section 

before trial. 

Thickness before trial. 

Area of the section 

before trial. 

Temperature Fahren¬ 

heit. 

Breaking weight in the 

scale. 

Breaking weight X le¬ 

verage. 

Friction. 

Effective strain. 

Strength in lbs. per 

square inch. 




1832. 











160 

L’gth. 

1 

May 2. 

30.2 

.862 

.136 

.117232 

60° 

245 

7350 

367 

6983 

59565 

160 

tt 

2 

U 

27.2 

.946 

.126 

.119196 

60 

250 

7500 

375 

7125 

59775 

160 

tt 

3 

U 

22.25 

1.000 

.130 

.130000 

60 

257 

7710 

385 

7325 

56346 

160 

tt 

4 

U 


.612 

.124 

.075888 

48 

175 

5250 

262 

4988 

65725 

160 

it 

5 

May 7. 


1.016 

.130 

.132080 

60 

272 

8160 

408 

7752 

58691 

160 

ti 

6 

U 


1.040 

.134 

.139360 

60 

290 

8700 

435 

8265 

59307 

162 

L’gth. 

7 

May 9. 

30.2 

.858 

.136 

.116688 

69 

256 

7680 

384 

7296 

62526 

162 

tt 

8 

t 

U 

27.6 

.998 

.132 

.131736 

69 

262 

7860 

393 

7467 

56682 

162 

tt 

9 

1833. 

19.4 

1.000 

.136 

.136000 

69 

280 

8400 

420 

7980 

58677 

162 

tt 

10 

Jan. 24. 


.647 

.134 

.086698 

48 

225 

6750 

337 

6413 

73969 

162 

tt 

11 

U 


.750 

.114 

.085500 

49 

234 

7020 

351 

6669 

78000 

162 

tt 

12 

Jan. 26. 


.656 

.130 

.085280 

56.5 

224 

6720 

336 

6384 

74859 

164 

L’gth. 

13 



.747 

.132 

.098604 

576 

233 

6990 

349 

6641 

66336 

164 

tt 

14 

\ 


.711 

.135 

.095985 

87.5 

203 

6090 

304 

5786 

60280 

164 


15 



.731 

.138 

.100878 

87.5 

200 

6000 

300 

5700 

56503 

164 

tt 

16 



.734 

.140 

.102760 

87.5 

196 

5880 

294 

5586 

54361 

164 

tt 

71 



.780 

.139 

.108420 

578 

253 

7590 

379 

7211 

66510 

164 

tt 

18 



.683 

.135 

.092205 

74. 

198 

5940 

297 

5643 

61200 

164 

tt 

19 



.714 

.135 

.096390 

74. 

208 

6240 

312 

5928 

61500 


% 





















































125 


TABLE XLVII. 


f (method of refining not stated.) These strips cut off lengthwise of 
"j M ie sheet. Reduced in some instances by filing , and in others tried in 
ithe state in which they came from the shears. Specific gravity 7.7. 


o 

3 

*3 

C 


he 3 

• 3.2 


* 

a 


C 224 
C 245 

C 252 
l 257 


Sh i) 

cl .C 

32 t5 

0 ) 

33 . 
+■» >* 


m 
• m 
O w 

£ O . 
rt ^ — 

'=1 

<v 


W 


1 ° 22 ' 7 
Broke. 5 


1.04' 

Broke 


.} 


<m 

as 

u 

ci 

X 

o 

xs 

■M 

Cm 

%i 

<v S 

^ ** 


Cm 

O 

3 

.2 • 

<v U 

9 ) M 

0) fc, 

w cS 

cn Q 
CB u* 


30.85 

27.3 


C 262 0.42' 
£272 
C 280 
£ 290 


fl68 
j 224 
1 252 
1.256 


C 262 
£ 262 


Broke. ^ 
0.35' 7 
Broke. 5 


1 °. 00 ' 

1.05 

0.58* 

Broke. 


1°. 12' 7 
Broke. 5 


30.8 


.079764 

.090240 

.096304 

.101388 

.128000 


.079600 


28.0 


19.7 


103800 


.068701 

.047333 

.042560 

.041400 

.067800 

.043500 

.048030 


REMARKS. 


Broke at a filed section. 

Do. 

Do. 

Deeply filed section,bore 175 pounds, fora while 
sunk from 0 with it, but broke on taking up the screw. 

Unfiled section. 

Do. 


Broke at the filed section. 

* This elasticity taken within 4 lbs. of the break¬ 
ing weight. 

A section was filed on the sides to remove 
completely the scale of oxide from the bar at that 
part. But the fracture did not take place at the 
-/ filed section though its area was only .116820; 
while that of the section of fracture was .131736. 
Calculated on the section filed, the strength was 
above 63917 lbs per square inch. 

Original section. 

This experiment was on a deeply filed section. 
Do. 

Bore this weight for some time and then broke 
without addition. 


Fracture at the filed section forming a bevel like 
the cutting part of a mortising chisel. 

Fracture of the usual appearance of cold bars. 

Do. 

Broke immediately on applying this weight. 

This fracture smooth and sharp like the first ex¬ 
periment and of the same form. 

Fracture as usual in cold experiments. 

Do. Do. 































126 


TABLE XLVIII. 

Experiments on bar No. 146. Manufactured by Messrs. S. E. HP 
P. Ellicott. Rolled into boiler plate in the usual manner, and this ■ 
strip cut off lengthwise of the sheet. Reduced by filing, after having \ 
been cut with the shears. The dimensions of the specimen before trial J 


Dimensions taken after certain exp's, had been made or given n>hts. borne by the bar. 


Measures after a strain of 328 
pounds. Oct. 17, 18 32. 


cc 

s 

| Breadth. 

1 

Thickness. 

Area. 

j Marks. 

Breadth. 

Thickness. 

Area. 

1 

.888 

.200 

.177600 

1 

.874 

.198 

.173052 

5 

.888 

.200 

.177600 

2 

.865 

.196 

.169540 

8 

.891 

.200 

.178200 

3 

.867 

.192 

.166464 

12 

.882 

.204 

.179928 

4 

.869 

.192 

.166848 

13 

.882 

.203 

.179046 

5 

.868 

.199 

.182732 

17 

.880 

.209 

.183920 

6 

.857 

.199 

.170543 

m 

.886 

.209 

.185174 

7 

.857 

.195 

.167115 

m 

.882 

.207 

.182574 

8 

.866 

.197 

.170602 

Meas. taken after first frac. 

9 

.873 

.202 

.176346 

1 

.875 

.198 

.173250 

10 

.866 

.200 

.173200 

2 

.881 

.196 

.172676 

11 

.865 

.198 

.171270 

3 

.883 

.200 

.176600 

After the fourth fracture. 

4 

.883 

.197 

.173951 

1 

.870 

.197 

.171390 

5 

.879 

.200 

,175800 

2 

.856 

.193 

.165208 

6 

.874 

.200 

.174800 

3 

.848 

.190 

.161120 

7 

.873 

.200 

.174600 

34 

.847 

.187 

.158389 

8 

.880 

.200 

.176000 

4 

.855 

.192 

.164160 

9 

.879 

.201 

.176679 

5 

.860 

.195 

.167700 

10 

.879 

.202 

.177558 

6 

.843 

.198 

.166914 

11 

867 

201 

174267 





12 

.867 

200 

.173400 

After the seventh fracture. 

13 

.805 

! 191 

.153755 

1 

.862 

.196 

.168952 

134 

.788 

.165 

.130020 

2 

.854 

.192 

.163968 

14 

.845 

.198 

.167310 

3 

.848 

.189 

.160272 

15 

.862 

.201 

.173262 

34 

.846 

.187 

.158202 

16 

.868 

.204 

.177072 

4 

.855 

.192 

.164160 

17 

.865 

.205 

.177325 

5 

.859 

.196 

.168364 

18 

.880 

.203 

.178640 





19 

.872 

.201 

.175272 





20 

.875 

.203 

.177625 





21 

.874 

.201 

.175674 





22 

.884 

.202 

.178568 





23 

.883 

.207 

.182781 





24 

.866 

207 

179262 





25 

.873 

.205 

.178965 






After the second fracture. 


After the 6th experiment. 


£ 

GC 

00 

<D 

c 


V) 

ns 



3 

y 

IS 

y 

s 


h 

< 

16 

.861 

.201 

.173061 

17 

.856 

.201 

.172056 

18 

.873 

.202 

.176346 

19 

.868 

.200 

.173600 

20 

.856 

.200 

.171200 

201 

.854 

.200 

.170800 

21" 

.858 

.199 

.170742 

22 

.869 

.200 

.173800 

23 

.866 

.200 

.173200 

24 

.848 

.197 

.167056 

244 

.838 

.199 

.166762 

25 

.863 

.201 

.173463 

After the tenth fracture. 

16 

.844 

.202 

.170488 

17 

.852 

.201 

.171252 

18 

.866 

.202 

.174932 

19 

.851 

.200 

.170200 

20 

.854 

.199 

.169946 

21 

.855 

.197 

.168435 

22 

.863 

.200 

.172600 

23 

.861 

.201 

.173061 

24 

.794 

.180 

.142920 

During the 14th experiment 


smallest section* 


.835 

.193 

.161155 

18 

.864 

.200 

.172800 


No. of the experiment. 

DATE. 

1 

1832. 

Oct. 20. 

2 

U 

3 

Oct. 27, 

4 

u 

5 

Nov. 3, 

6 

u 

7 

Nov.10, 

8 

u 

9 

a 

10 

a 

11 

u 

12 

Nov. 15, 

13 

« 

14 

a 


ps« 


566 


580 


545 


550 


580 

560 

52 

52 

52 

547 

500 

90 

80 

70 





























































127 


TABLE XLVIII. 

fweie, length 25^ inches , breadth .893, and thickness .207, giving the 
• area of cross sections=. 184851 of a square inch. Marked and num¬ 
bered before trial at every inch of the length. Spec. grav. 7.739. Origi- 
l^nat dimensions before filing, 1.01 X.24=.242400, area of section. 


Breaking weight in 

the scale. 

Br. weight X lever¬ 

age. 

Friction. 

Effective strain. 

Strength in lbs. per 

square inch. 

Point fractured. 

393 

11790 

589 

11201 

60594 

No. 13^ 

424 

12720 

636 

12084 

65371 

“ 12 

437 

13110 

655 

12455 

67378 

r Broke be- - ^ 
2 tween the > 
C wedges. J 

446 

13380 

669 

12611 

68222 

“ 6* 

405 

12150 

607 

11543 

62445 

“ 15.1 

431 

12930 

646 

12284 

66453 

Not parted. 

462 

A63 

13860 

13890 

693 

694 

13167 

13196 

71253 

71387 

C At a part') 
ungauged 
(.near No. l.J 

“ 5* 

469 

14070 

703 

13367 

72312 

“ 5 

467 

14010 

700 

13310 

72004 

“ 24 

464 

13920 

696 

13224 

71539 

{ Within the ) 
i wedges. j 

476 

14280 

714 

13566 

73389 

Not noted. 

477 

14310 

715 

13595 

t 

73546 

Do. 

485 

14550 

727 

13823 

74779 

Near 18. 


REMARKS. 


F 


Part in hot oil from 1 to 5; in ice from 20£ 
to 24^. Strained with 328 lbs. then gauged 
d. as stated. Increase of length by that wht. 

| .3 inch in 25.5. When the oil was 566,° 
Lthe part at No. 9 was at 212°. 

C When put in, this piece measured 13.85 
C inches in length. After frac. it was 14.6. 
This fracture took place at the coldest part, 
say at about 100°. After frac. one portion 
viz. from 9 to 10, was found to measure in 
LBreadth. .760, Thick. .163, Area .123880. 
Before this fracture was made, the bar had 
been put under a strain of 429 lbs. and a tem¬ 
perature of 545°. Then suffered to cool 
down to 56°. By again heating it up to 
446 the index fell 33', and by raising the 
^temperature to 540° it fell in all 48'. 

Fracture near the wedges. This and the 
following experiment were made on a dif¬ 
ferent part of the bar from the preceding. 
r Part in oil from 14 to 18. At the temp. 
I and wht. here recorded the oil accidentally 
took fire, which caused the experiment to 
be suspended. The bar was subsequently 
heated again in experiment 10th. 

C After this experiment this part of the bar 
w r as again gauged. 

Fracture just within the wedges, 
r Frac. very bright and crystalline-directly 

< across-with little diminution of area-a flaw 
( now appears in this part of the bar. 

C Part now in, is from 16 to 24^, same part 

in oil as in the 6th experiment, 
r The point of frac. was judged to be heated 

< to above 130° as it could not conveniently 
Cbe held in the hand. 

C The temperature marked in this experi- 
t ment is only approximate. 

C After the weight 485 had been applied the 

< bar was taken out and gauged, then return- 
( ed and broke, but not at the smallest sect. 


I 


11 * 




















128 


TABLE XLIX. 


Experiments on bar No. 149. Manufactured into boiler plate byl 
Messrs. S. E. H. fy P. Ellicott. The ore obtained on the Patapsco, 8 y 
miles from Baltimore ; rolled in the usual manner , and this strip cut J 


Marks. 

Breadth 

Thickness. 

Area before trial at the 
points measured. 

No. of the experiment. 

DATE. 

Area of the section of 

fracture before trial. 

Temperature Fahren¬ 

heit. 

Breaking weight in the 

scale. 

Breaking weight mul¬ 

tiplied by leverage. 

Friction. 

Effective strain. 

0 

.762 

.248 

.188976 


1833. 







1 

.762 

.247 

.188214 

1 

Oct. 10, 

.180357 

66 

334 

10020 

501 

9519 

2 

.760 

.242 

.183920 









3 

.760 

.242 

.183920 









4 

.760 

.243 

.184680 

2 

il 

.182259 

750 

334 

10020 

501 

9519 

5 

.761 

.248 

.188728 




approx. 





6 

.760 

.248 

.188480 

3 

Oct. 12, 

.184680 

61 

369 

11070 

553 

10517 

7 

.760 

.245 

.186200 

4 

a 

.186770 

61 

371 

11130 

556 

10574 

8 

.760 

.243 

.184680 

5 

it 

.183920 

62 

375 

11250 

562 

10688 

9 

.761 

.237 

.180357 

6 

u 

.188666 

62 

380 

11400 

570 

10830 

10 

.762 

.242 

.184404 









11 

.762 

.246 

.187452 









12 

.762 

.240 

.182880 

7 

(( 

.185669 

825 

369 

11070 

553 

10517 

13 

.762 

.237 

.180594 









14 

.762 

.239 

.182118 









15 

.760 

.240 

.182400 

8 

u 

.182309 

63.5 

380 

11400 

570 

10830 

16 

.760 

.240 

.182400 









17 

.761 

.240 

.182640 









18 

.761 

.239 

.181879 









19 

.762 

.240 

.182880 

9 

<t 

.183381 

770 

356 

10680 

534 

10146 

20 

.763 

.240 

.183883 









21 

.763 

.244 

.186172 









22 

.764 

.241 

.184124 









23 

.763 

.243 

.185409 

10 

Oct. 17, 

.182400 

69 

397 

11910 

595 

11315 

24 

.763 

.245 

.186935 

11 

(l 

.182630 

69 

397 

11910 

595 

11315 

25 

.762 

.242 

.184404 

12 

<( 

.184455 

69 

403 

12090 

604 

11486 

26 

.762 

.240 

.182880 

13 

(« 

.185088 

69 

410 

12300 

615 

11685 

27 

.762 

.238 

.181356 

14 

(< 

.182118 

69 

401 

12030 

601 

11429 

28 

.762 

.239 

.182118 









29 

.769 

.235 

.180715 


Mn. of 14 = 

.183907 







Mean of 30 .184193 


Maximum . 188976 
Minimum .180357 


Mn. of the 2.184666 
Diff. of the 2 .008619 




























129 


TABLE XLIX. 

off by the shears across the direction of the rolling. Reduced by filing 
from about one inch in breadth and 4 inch in thickness to the dimen¬ 
sions recorded . Specific gravity , 7.7774. 


Strength in lbs. per 

sq. inch. 

Point of fracture. 

52778 

No. 9 

52228 

“ 14| 

56947 

“ 8 

56615 

“ 6} 

58112 

a 01 
"3 

57403 

“ 5! 

56644 

“ 24! 

59494 

“ 12! 

54781 

“ 19! 

62034 

“ 15! 

61955 

“ 18! 

62269 

“ 20J 

63132 

“ 22| 

62755 

“ 28 



More than 24 inches under trial. After several trials to ascer¬ 
tain the weight producing the first permanent extension, it was 
found to be attained with 224 pounds in the scale. 

Part in tin from 13 to 164 Too much water in the pyrome¬ 
ter—dashed over a little. The No. 7804-212, originally marked, 
is certainly too high. 

The part now under trial was that broken off in the first exp. 


C The part now in is from 22 to 254 The bar stretched for some 
j time, and as the furnace was not lowered, the standard piece 

t had probably at the moment before taking the temperature 
attained a greater degree of heat than was absolutely neces 
sary to break the bar under this weight. 

Part in metal from 18 to 21. The temperature was raised 
gradually until the bar appeared, about to give way; then 
lowered the furnace and diminished the heat till the lever 
<( ceased to descend. Repeated this three times and at last 
when a decided evidence of fracture was given the tempera 
ture was taken with care, and is therefore regarded as very 
correct. 


Broke in the gripe of the wedges. 


The mean area of the sections of fracture is .000286 square 
inch less than the mean area of the measured sections. 
















130 


TABLE L. 

Experiments on bar No, 150. Manufactured by Messrs. S. E. 
H. P. Ellicott. The ore obtained on the Patapsco , 8 miles from - 
Baltimore. Rolled in the usual manner , and this strip cut off by ^ 


0 

1 

2 

3 

4 

5 

6 

7 

8 
9 

10 

11 

12 

13 

14 

15 

16 

17 

18 

19 

20 
21 
22 

23 

24 

25 

26 
27 


4/ 1/ 

5.o 


.SX3 

w i) 

v U) 



Vi 

<h 

P 

CS 

'S 

as 

<u 

O 

2 2 _ 

u 

n 

h 

<.2 as 

O T 




.719 

.236 

.169684 

.720 

.236 

.169920 

.721 

.236 

.170156 

.718 

.237 

.170166 

.720 

.234 

.168480 

.717 

.236 

.169212 

.722 

.236 

.170392 

.722 

.236 

.170392 

.722 

.235 

.169670 

.721 

.234 

.168714 

.718 

.234 

.168012 

.717 

.232 

.166344 

.721 

.232 

.167272 

.719 

.232 

.166808 

.717 

.231 

.165627 

.724 

.232 

.167968 

.724 

.232 

.167968 

.723 

.231 

.167013 

.721 

.230 

.165830 

.721 

.232 

.167272 

.722 

.234 

.168948 

.723 

.235 

.169905 

.722 

.233 

.168226 

.721 

.234 

.168714 

.723 

.237 

.171351 

.725 

.237 

.171825 

.722 

.233 

.168226 

.720 

.234 

.168480 

.719 

.232 

.166808 


DATE 


1833. 
Sept. 26, 


U 


Sept. 28, 


U 


Mean of 29= .168599 


Maximum= 
Minimum = 


.171825 

.166344 


Mn of these 2 .169084 


Diff*. of the 2 .004491 


Oct. 3, 


« 


a 


16 


Area of the section 

of fracture btfore trial. 

| Temperature, Fah. 

Breaking weight in 

the scale. 

Breaking weight X 

leverage. 

Friction. 

Effective strain. 

Strength in lbs. per 

square inch. 

i 


o 






.166020 

81 

346 

10380 

519 

9861 

59397 

.169485 

662 

346 

10380 

519 

9861 

58182 

.168470 

75 

345 

10350 

517 

9833 

58366 

.166808 

75 

380 

11400 

570 

10830 

64925 

.170301 

734 

346 

10380 

519 

9861 

57903 

.168714 

68 

368 

11040 

552 

10488 

62164 

.167272 

68 

382 

11460 

573 

10887 

65086 

.170392 

68 

340 

10200 

510 

9690 

56869 

.169605 

68 

361 

10830 

541 

10289 

60664 

.169684 

68 

368 

11040 

552 

10488 

61809 

.169920 

68 

377 

11310 

565 

10745 

63235 

.170166 

68 

388 

11640 

582 

11058 

64983 

.167226 

63 

386 

11580 

579 

11001 

65785 

.170692 

63 

388 

11640 

582 

11058 

64783 

.168311 

63 

388 

11640 

582 

11058 

65700 

.167963 

63 

359 

10770 

538 

10232 

60917 

.167272 

63 

372 

1116C 

558 

10602 

63382 

.166615 

.168606 

63 

.382 

1 

1146C 

578 

10887 

65342 


bn 

P 

3 

O 


% P 
•P O 

Qj 

£ bC 


< 


n9 6 
294 
301 
308 
315 
322 
329 
336 
343 
346 











































































131 


TABLE L 


Cthe shears, across the direction of the rolling. Reduced by filing from 
i about, one inch m breadth and one-fourth inch in thickness, to the di- 
l mensions recorded. Specific gravity , 7.7774. 


*■£ . 

o c 

zs 

0; ^3 

i- be 

1-1 
CD D75 

1/5 -C . 

o w £ 

C** QJ 

O £ 


1st perm, elong. 

.30 

in 24 in. 

.40 

U . 

.50 

U 

.60 

U 

.73 

u 

.90 

u 

1.14 

u 

1.42 

a 

Br. as per rec. 




'O 

4) 

fc< 

s 

u 

rt 


O 

Qu 


REMARKS. 


No. 13f 


“ 21 * 


(« 


<< 


<( 


« 


«« 


22 1 


28^ 

n 


9 

12 

6 * 

H 

0 

1 


“ 27f 
“ 23| 
« 26^ 


‘‘ 15 


<< 

<< 


19 

m 


C The temperature is perhaps not quite accurate on ac- 
s count of the standard piece having fallen. Part in tin 
C.from 19 to 23. Broke in the tin. 

Broke at a part which had been heated. 

Part in tin from 4^ to 8£. 


Broke very soon after the weight was applied. 

Not heated. 

( When the weight had been added to the amount of 
J 383 lbs. the machine was relieved and oiled to ascer- 
j tain whether the friction had before been above our 
l_estimate ; but no effect was perceptible. 


Part now under trial from 13f to 21. Fracture 
shows three distinct laminae, of which the central one 
appears more coarse grained than the two outside ones. 


The mean area of 18 fractures, is .000007 square 
inch greater than the mean area of the 29 measured 
sections. 


















132 


TABLE LI. 

Experiments on bar No. 152. Manufactured by Messrs. S. E. H. 'i 
fy P. Ellicott. The ore obtained on the Patapsco , eight miles from 
Baltimore. Rolled into boiler plate and this strip cut across the sheet. J 


Marks. 

Breadth. 

Thickness. 

Area of section at the 
points measured. 

No. of the experiment. 

DATE. 

Area of the section of 

fracture. 

Temp. Fah. 

Breaking wht. in the 

scale. 

Breaking weight x 

leverage. 

Friction. 

Effective strain. 

Strength in lbs. per 

sq. inch. 

0 

.733 

.232 

.170056 


1833. 








1 

.733 

.233 

.170789 

1 

Sept. 14. 

.171230 

66 ° 

348 

10440 

522 

9918 

57922 

2 

.733 

.235 

.172255 










3 

.733 

.235 

.172255 

2 

u 

.173327 

66 

341 

10230 

511 

9719 

56073 

4 

.733 

.235 

.172255 










5 

.731 

.236 

.172516 

3 

u 

.173195 

66 

348 

10440 

522 

9918 

57405 

6 

.735 

.236 

.173460 



? 







7 

.729 

.236 

.172044 

4 

u 

.172752 

722 

330 

9900 

495 

9405 

54442 

8 

.735 

.236 

.173460 










9 

.735 

.236 

.173460 










10 

.735 

.234 

.171990 

5 

Sept. 19. 

.169050 

1037 

224 

6720 

336 

6384 

37764 

11 

.735 

.231 

.169785 










12 

.735 

.233 

.171255 










13 

.735 

.235 

.172725 










14 

.735 

.233 

.171255 

6 

Sept. 21. 

.172490 

80 

336 

10080 

504 

9576 

55516 

15 

.735 

.230 

.169050 










16 

.735 

.233 

.171255 

7 

U 

.170770 

80 

350 

10500 

525 

9975 

58412 

17 

.735 

.230 

.169050 










18 

.734 

.235 

.172490 

8 

u 

.171990 

80 

336 

10080 

504 

9576 

55678 

19 

.737 

.236 

.173932 










20 

.737 

.235 

.173195 

9 

ii 

.172358 

80 

340 

10200 

510 

9690 

56220 

21 

.737 

.235 

.173195 










22 

.737 

.235 

.173195 

10 

u 

.171990 

80 

373 

11190 

559 

10631 

61809 

23 

.735 

.236 

.173460 










24 

.735 

.233 

.171255 

11 

u 

.170056 

80 

352 

10560 

528 

10032 

58992 

25 

.736 

.233 

.171488 










26 

.737 

.233 

.171721 

12 

u 

.173106 

80.5 

375 

11250 

562 

10688 

61742 

27 

.737 

.232 

.170984 










28 

.738 

.230 

.169740 

13 

u 

.172342 

80.5 

379 

11370 

568 

10802 

62677 

Mean of 29 .171847 

14 

u 

.172255 

80.5 

379 

11370 

568 

10802 

62709 


Maximum .173932 


Mn. of 14 = 

=.171922 








Minimum .169050 
Mn. of these 2.171491 
Diff. of the 2.004882 





























I 


133 

TABLE LI. 

C Reduced by filing from, one inch in breadth to the dimensions re- 
< corded , and gauged at every inch , from 0 to 28 inclusive. Specific 
i gravity , 7.7774. 


/"Measured after this exp. 


.640 

J 87 pel¬ 
's cent. 

I of ori. 
1 br’th. 


L 


.198 

81.7 
pr. ct. 
of ori. 
thick. 


.126720 

74.3 per ct. I 
of the oriel- r 
wal area. 


*5 

a> 

u 

3 

-*-> 

o 

a 

£ 


o 

pH 


No. 

263 

m 

20f 

n 

15 


18 


17* 


13* 


12 | 

10 

0 

63 

4* 

33 


REMARKS. 


Broke very soon after applying the wht. recorded. 

Broke by a gradual application of weights. 

Fracture oblique to the bar. 

At this trial the condenser of the steam pyrome¬ 
ter was employed. When the equilibrium had 
been reproduced by the revolving weight it con¬ 
tinued without the slightest alteration for half an 
i_hour. 

Broke at the part heated—a flaw discovered in the 
interior of the bar. 


f 


1 


Broke on first applying the weight—result sup¬ 
posed rather too high. 


The mean area of the sections of fracture is 
.000075 greater than the mean area of the 29 mea¬ 
sured sections. 















134 


TABLE LII. 

Experiments on bars No. 200 and 201, cross strips , and on 206, 207 
Gerard Ralston , Esq. 


No. of the bar. 

Direction of the slit. 

DATE. 

No. of the exp’t. 

Breadth before trial. 

Thickness before trial. 

Areas of section be* 

fore trial. 

Tempex-ature, Fah. 

Bi*eaking weight in 

the scale. 

Breaking weight X 

levei*age. 

Fi-iction. 

200 

Cross. 

1833. 
Aug. 4, 

1 

.760 

.160 

.121600 

81.° 

226 

6780 

339 

200 

ft 

tt 

2 

.658 

.160 

.105280 

81. 

190 

5700 

285 

200 

<( 

it 

3 

.778 

.166 

.129148 

81. 

182 

5460 

273 

201 

Cross. 

tt 

4 

.645 

.159 

.102555 

81. 

169 

5070 

253 

206 

Length. 

tt 

5 

.697 

.165 

.115005 

81. 

216 

6480 

324 

206 

<( 

tt 

6 

.500 

.165 

.082500 

81. 

163 

4890 

244 

206 

it 

tt 

7 

.807 

.164 

.132348 

81. 

205 

6150 

307 

206 

tt 

tt 

8 

.657 

.164 

.107748 

81. 

192 

5760 

288 

206 

tt 

tt 

9 

.753 

.165 

.124245 

81. 

213 

6390 

319 

206 

tt 

tt 

10 

.663 

.167 

.110721 

80. 

196 

5880 

294 

206 

tt 

tt 

11 

.594 

.166 

.098604 

80. 

203 

6090 

304 

207 

Length. 

Aug. 1, 

12 

.654 

.166 

.108564 

572.5 

251 

7530 

376 

207 

(( 

46 

13 

.674 

.167 

.112558 

580. 

248 

7440 

372 

207 

tt 

tt 

14 

.664 

.167 

.110888 

78. 

212 

6360 

318 

207 

tt 

tt 

15 

.720 

.167 

.120240 

84. 

203 

6090 

304 

207 

tt 

46 

16 

.666 

.167 

.111222 

573.5 

245 

7350 

367 

207 

tt 

tt 

17 

.658 

.167 

.109886 

84. 

190 

5700 

285 

207 

tt 

tt 

18 

.730 

.166 

.121180 

84. 

230 

6900 

345 

207 

tt 

66 

19 

.680 

.168 

.114240 

84. 

215 

6450 

322 

208 

Length. 

tt 

20 

.662 

.167 

.110554 

1000 . 

112 

3360 

168 

208 

tt 

tt 

21 

.725 

,162 

.117450 

appr. 

84. 

215 

6450 

322 


























































135 


TABLE LII. 

and 208, length strips , from a sheet of English boiler-iron , furnished by 


Effective strain. 

Strength in lbs. per 
square inch. 

6441 

52968 

5415 

51434 

5187 

40163 

4817 

46970 

6156 

53528 

4646 

56315 

5843 

44149 

5472 

50786 

6071 

48863 

5586 

50451 

5786 

58679 

7154 

65897 

7068 

62794 

6042 

54487 

5786 

48120 

6983 

62786 

5415 

49278 

6555 

54093 

6128 

53641 

3192 

28876 

6128 

52175 


{ 


REMARKS. 


Original breadth of the bar about one inch.—Broke at a 
filed section. 


Do. 

Do. 


C This result is probably rather too high, as the weight 
£ 169 lbs. broke the bar in a very short time. 


l 

l 


Broke at a filed section. 

About one-half of the original section was filed away to 
be sure of escaping the weakening effect of the shears. 

The section now filed was obviously not deep enough. In 
a trial not recorded, a fracture was made entirely out of this 
filed part. 

The low result is here, probably, to be in part attributed to 
the deficiency of filing. 


r This experiment and No. 2. were certainly made on sections 
£ sufficiently filed to test the full strength of the metal. 


All the experiments on this bar, (No. 207,) were made at 
| sections more or less filed. It was originally about one inch 
| wide, and .167 inch in thickness. The filing was, in general, 
) confined entirely to the edges, and not extended to the flat 
^surfaces which had been exposed to the rolls. 


Heated by the flame of a spirit lamp applied directly under 
the bar. Pieces of rolled zinc were melted on the upper sur¬ 
face of the bar before it parted. 


12 




























136 


TABLE LIII. 


Experiments on bar No. 226. Boiler-plate iron. Manufactured by 
Messrs. Evan T. Ellicolt fy Co., of Baltimore. Origin of the metal and 
mode of manufacture not specified; supposed to be lamellated. This 


Marks. 

at 

CJ 

Thickness. 

Area of measured 
sections before trial. 

1 

+-> 

r p~ 

V 

Qj 

W 

© 

c 

£ 

DATE. 

Ai*ea of the section 
of fracture. 

1 

Temperature, Fah. 

Breaking weight in 

the scale. 

Breaking weight X 

leverage. 

Friction. 

Effective strain. 

Strength in lbs. per 

square inch. 

0 

.763 

.244 

.186172 










1 

.762 

.244 

.185928 


1834. 








2 

.761 

.240 

.182640 

1 

June 21. 

.183026 

o 

o 

00 

315 

9450 

472 

8978 

49053 

3 

.762 

.234 

.178308 










4 

.762 

.241 

.183642 










5 

.760 

.241 

.183160 










6 

.760 

.241 

.183160 

2 

<* 

.181799 

80. 

351 

10530 

526 

10004 

55028 

7 

.760 

.239 

.181640 










8 

.760 

.238 

.180880 










9 

.760 

.240 

.182400 










10 

.759 

.242 

.183678 

3 

<« 

.177992 

1237. 

133 

3990 

199 

3791 

21298 

11 

.759 

.241 

.182919 










12 

.762 

.242 

.184404 










13 

.762 

.240 

.182880 

4 

June 28. 

.183600 

73.75 

351 

10530 

526 

10004 

54488 

14 

.761 

.239 

.181879 










15 

.760 

.238 

.180880 










16 

.760 

.240 

.182400 










17 

.760 

.242 

.183920 

5 

<< 

.180880 

1317. 

120 

3600 

180 

3420 

18913 

18 

.756 

.239 

.180684 










19 

.757 

238 

.180066 










20 

.753 

.235 

.176955 










21 

.757 

.233 

.176381 










22 

.767 

.240 

.184080 










23 

.765 

.240 

.183600 

6 

if 

.180880 

1192. 

120 

3600 

180 

3420 

18913 

24 

.765 

.240 

.183600 










25 

.761 

.239 

.181879 










26 

.760 

.239 

.181640 

7 

July 2. 

.180684 

83. 

280 

8400 

420 

7980 

44165 

27 

.761 

.259 

.181879 

a 









28 

.766 

.237 

.181542 

8 

ft 

.183109 

1245. 

133 

3990 

199 

3791 

20703 

Mean of 29 

.182144 











Maximum 

.186172 

9 

u 

.183160 

1142. 

120 

3600 

180 

3420 

18672 


Minimum 

.176381 










Mn. of the 2 

.181276 

10 

July 30. 

.181629 

80. 

275 

8250 

412 

7838 

43154 





11 

t < 

.182630 

80. 

306 

9180 

459 

8721 

47752 

Diflt. of the 2 .009791 

12 

t ( 

.183425 

80. 

250 

7500 

375 

7125 

38843 




* 

13 

ft 

.181640 

80. 

285 

8550 

427 

8123 

44720 





14 

<« 

.183160 

80. 

301 

9030 

451 

8579 

46839 





15 

< t 

.183522 

80. 

343 

10290 

514 

9776 

53269 





16 

ft 

.180086 

80. 

370 

11100 

555 

10545 

58551 





17 

if 

.185928 

80. 

382 

11460 

573 

10887 

58555 





Mean of 17 

.182185 








4 























































137 


TABLE LIII. 

'strip was cut off in the direction crosswise of the sheet , reduced by filing 
from 1 inch in breadth and 4 inch thick , to the dimensions given be¬ 
low. Specific gravity , 7.7428. 


to 

.£ 

3 

*3 

O 


~ O 


r? 

<V 

c 

3 

*3 

O 


3 

o 


il) C3 

> to 
c 
© 

© 

«-» 

w 

f238 

No perm, elonga. 

245 

Elonga. decided. 

•<( 280 

24.86 (wt.off, 24.82) 

314 

25.5, gain 1 1-2 in. 

L315 

Broke. 


*3 

© 


© 

cs 


o 


No. 244 


“254 


“ m 

“ 24 

“ 15 


“ 15 

“ 18 
“ 10| 

«< 


‘ 144 
* 134 
‘loi 
‘ 7 
‘ 54 
‘ 44 
‘ 34 
< 


>3 

1 


REMARKS. 


r Began the experiments on this bar by adding weights 
) gradually from 210 lbs., and observing on a length of 
24 inches, both when under strain and when relieved, 
V_the actual length of that portion. Cold fracture. 


< Fracture in the short piece broken off in the first 
( experiment. 

T Part heated from 17 to 21. The temp, was twice raised 
| to the point of yielding. After the first trial it was 
j allowed to abate; then raised again and broke the bar. 
<2 If any variation from the true breaking heat existed, it 
j was conjectured to be a trifle too high. But exp ! t 8 
l proves it to have been right, {see below.) The iron was 
{.distinctly red in day-light. 


f In hot metal from thirteen to sixteen and a half. The 
temp, having been raised to the point where the bar had 
begun to yield rapidly, the fire was removed after taking 
that temp, by the pyrometer. The lever at length ceased 
to descend, and soon came to rest as the metal cooled. 
Distinctly red in day-light. As the bar was sometime 
strained with this weight, it had probably been so weak 
ened as not again to require the same temperature. 

C Part in metal from thirteen to sixteen and a half. The 
| temp, had not risen so high as in the preceding trial 
J when the bar began again to extend, and finally gave 
' way. The heat was carefully managed by means of the 
j suspended furnace and lever to avoid any excess. 

|^so red as before,—barely distinguishable in dusk. 


Not 


C In tin from 8 to 12. This exp’t, like the sixth, was 
< made carefully by lowering the fire, when the bar ap- 
( peared to be stretching too rapidly. Red in day-light. 

r This fracture was doubtless made on a part of the bar 
| which had been originally defective. The section of 
<J fracture was much less reduced than in the preceding 
j trial, and was flaky in appearance. Not visibly red in 
{^day-light. 


The mean area of the 17 sections of fracture is greater 
by .000041 sq. inch, than the mean area of the 29 measured 
sections. 



















138 


TABLE L1V. 

Experiments on bar No. 227. Manufactured into boiler plate by > 
Messrs. E. T. Ellicott fy Co., of Baltimore. The mode of manufacture, $ 


Marks. 

Breadth. 

Thickness. 

Area at the points 
measured before trial. 

No. of the experiment. 

DATE. 

Area of the section of 

fracture before trial. 

Temp. Fah. 

Breaking weight in 

the scale. 

Breaking weight X 

leverage. 

Friction. 

Effective strain. 

0 

.765 

.235 

.179775 


1834. 


o 





1 

.765 

.236 

.180540 

1 

May 31, 

.181005 

70 

342 

10260 

513 

9747 

2 

.767 

.237 

.181779 

2 

u 

.181512 

70 

349 

10470 

523 

9747 

3 

.764 

.237 

.181068 









4 

.766 

.233 

.178478 









5 

.766 

.232 

.177712 









6 

7 

.766 

.767 

.236 

.235 

.180776 
.180245 

3 

June 7, 

.180421 

1097 

174.75 

5242.5 

262.12 

4980.38 

8 

.768 

.235 

.180480 









9 

.766 

.235 

.180010 









10 

.764 

.235 

.179540 









11 

.767 

.236 

.181012 









12 

.767 

.233 

.178711 

4 

u 

.180437 

1111 

174.75 

5242.5 

262.12 

4980.38 

13 

.767 

.236 

.181012 









14 

.767 

.236 

.181012 









15 

16 

.769 

.769 

.236 

.238 

.181484 

.183022 

5 

June 14, 

.182035 

1187 

140 

4200 

210 

3990 

17 

.767 

.238 

.182546 









18 

.767 

.237 

.181779 









19 

.767 

.239 

.183313 

6 


.181632 

1155 

140 

4200 

210 

3990 

20 

.768 

.236 

.181248 









21 

.768 

.235 

.180480 









22 

.768 

.236 

.181248 

7 

it 

.180500 

100 

348 

10440 

522 

9918 

23 

.768 

.237 

.182016 









24 

.767 

.237 

.181779 

8 


.178733 

90 

397 

11910 

595 

11315 

25 

.767 

.237 

.181779 

9 

June 21, 

.180363 

75 

350 

10500 

525 

9975 

26 

767 

.237 

.181779 

10 

June 28, 

.181897 

73.75 

291 

8730 

436 

8294 

27 

762 

.239 

.182118 

11 

(t 

.181779 

73.75 

341 

10230 

511 

9719 

28 

.768 

.237 

.182016 

12 

tt 

.181779 

73.75 

344 

10320 

516 

9804 





13 

u 

.181868 

73.75 

333 

9990 

499 

9491 






Mean of 29= 

.180997 

14 

July 2, 

.182290 

84 

288 

8640 

432 

8208 





15 

44 

.182280 

84 

300 

9000 

450 

8550 






Maximum= 

Minimum= 

.183313 

.177712 










Mn.of 15 = 

.181182 






Mn. of the 2 

.180512 









Diff. of the 2 

.005601 














































139 


TABLE LIV. 

source of the ore, kind of pig-metal, <^c. not specified. Specific gra¬ 
vity, 7.6675. This bar cut off crosswise of the sheet. 


Strength in pounds 

per square inch. 

Point of fracture. 

REMARKS. 

53849 

No. 1§ 

A short portion only embraced in the space between the wedges. 

53699 

“ 2§ 

Do, Fracture near the gripe of the wedges. Short piece. 

Part in melted metal from 6 to 9^. Compound of tin and lead 
used to float the standard-piece. Mean area of the sections of 7, 
8 , 9,and 9# is .180245. In order to ascertain the temperature re- 
J quired to break the bar with half the weight used in the pre- 
} ceding experiment, a calculation was made and this mean area 
found to require 174# pounds, which were accordingly applied. 

J The standard piece rose a little way out of the melted metal 
(just before fracture. 

r Part in tin from 11 to 14 inclusive. This experiment was 

27604 

“ n 

i 

27602 

21919 

“ 12# 

“ 17# 

< conducted so as to avoid loss, and may be regarded as, on the 
C whole, rather preferable to the preceding in point of accuracy, 
r In melted metal from 17 to 20 inclusive. When the fracture 
) took place the bar had been extending rapidly for some time, 

] and as the furnace was not lowered, would probably have broken 
kwith less weight. 

C In metal from 21 to 24. Broke gradually by keeping down 

21967 

“ 22j 

< the heat and preventing an excess above what was actually 
C. necessary to continue the extension of the bar. 

C This temperature was only j udged of approximately on account 

54947 

“ 6# 

< of the heat imparted to the machine by the preceding experi- 
C ment. 

63307 

“ 5i 

Machine still warm. 

55305 

“ 8i 


45597 

“ 23£ 


53466 

“ 24# 


53933 

“ 25l 


52186 

“ 15# 

This part of the bar appeared very defective from flaws. 

45027 

“ 18? 

46906 

“ 19# 

The mean area of the 15 sections of fracture is .000185 square 
nch greater than that of the 29 measured sections. 


12* 
















140 


TABLE LV. 

Experiments on bar No. 228. Manufactured by Messrs. E. T. Elli- £ 
cott fy Co., of Baltimore. The mode of manufacture, source of the ore, 5 


Marks. 

Breadth. 

Thickness. 

: 

Area of section before 
trial. 

Number of the ex¬ 
periment. 

DATE. 

Area of the section 

of fracture before trial. 

Temperature, Fah. 

Breaking weight in 

the scale. 

Breaking weight X 

leverage. 

Friction. J 

0 

.762 

.243 

.185166 








1 

.755 

.244 

.184220 








2 

.758 

.245 

.185710 


1834. 






3 

.758 

.245 

.185710 

1 

Aug 6. 

.186528 

o 

00 

266 

7980 

399 

4 

.762 

.245 

.186690 








5 

.760 

.242 

.183920 








6 

.758 

.242 

.183436 








7 

.760 

.246 

.186960 

2 

a 

.183436 

87 

287 

8610 

430 

8 

.759 

.248 

.188232 








9 

.758 

.248 

.187984 

3 

ii 

.185710 

87 

305 

9150 

457 

10 

.752 

.247 

.185744 








11 

.754 

.244 

.183976 

4 

ii 

.185710 

87 

367 

11010 

550 

12 

.754 

.243 

.183222 








13 

.760 

.243 

.184680 








14 

.762 

.246 

.187452 

5 

ii 

.187984 

87 

312 

9360 

468 

15 

.761 

.247 

.187967 








16 

.762 

.243 

.185166 








17 

.762 

.248 

.188976 

6 

ii 

.183222 

87 

317 

9510 

475 

18 

.762 

.250 

.190500 








19 

.762 

.246 

.187452 








20 

.755 

.247 

.186485 

7 

ii 

.187967 

87 

319 

9570 

478 

21 

.757 

.252 

.190764 








22 

.754 

.252 

.190008 








23 

.757 

.248 

.187736 

8 

it 

.190500 

87 

340 

10200 

510 

24 

.757 

.248 

.187736 








25 

.761 

.249 

.189489 

9 

ii 

.184730 

85 

342 

10260 

513 

26 

.760 

.249 

.189240 








27 

.758 

.245 

.185710 

10 

ii 

.187475 

85 

359 

10770 

538 

26 

.754 

.245 

.184730 












11 

ii 

.187555 

85 

361 

10830 

541 


Mean of 29 .186748 












12 

it 

.190008 

85 

361 

10830 

541 


Maximum .190764 









Minimum .183222 

13 

if 

.187736 

85 

363 

10890 

544 


Mean of these 2 .187493 

Mean of K 

3 .186811 






Diff. of the 2 .097542 




























































141 


TABLE LV. 


kind of pig-metal , fyc. not stated. This bar cut crosswise of the sheet. 
Specific gravity , 7.6675. 


Effective strain. 

Strength in lbs. per 
square inch. 

Point fractured. 

REMARKS. 




f The first permanent elongation was taken 

I with a weight of 232 lbs. With 238, the 

7581 

40643 

No. 13# 

<( extension was .146 inch on a length of 24 
| inches ; but the recoil .046 when relieved 
Lfrom strain. 

8180 

44593 

«• 6 


8693 

46809 

“ 3 


10460 

56324 

“ 2 

C The fracture took place with the weight first 

8892 

47302 

“ 9 

< applied—the result is therefore supposed to be 
C. too high. 

9035 

49263 

“ 12 

r Before this fracture was effected, the piece 

9092 

48370 

“ 15 

funder trial (from 16 to 27,) had become 11^ 
C inches long. 

9690 

50866 

“ 18 


9747 

52763 

“ 28 


10232 

54578 

“ 26^ 


10289 

54859 

«« 20# 


10289 

54150 

“ 22 


10346 

55109 

“ 23 

The mean area of the 13 sections of fracture 
is .000063 square inch greater than that of 29 
measured sections. 

. . 

















142 


TABLE LVI. 

Experiments on bar No. 229. Boiler plate iron. Manufactured by 
Messrs. E. T. Ellicott fy Co., of Baltimore. Origin of the metal , mode 
of manufacture , fyc., not specified. Supposed to be “lamellated plate,” 


Marks. 

Breadth. 

Thickness. 

Area of section before 
trial. 

1 

No. of the experiment. 

DATE. 

Area of the section of 

fracture before trial. 

Temperature Fah. 

Breaking weight in 

the scale. 

Breaking weight X 

leverage. 

Friction. 

Effective strain. 

Strength in pounds 

per square,inch. 

0 

.766 

.238 

.182308 


1833. 








1 

.766 

.240 

.183840 

1 

Dec. 28, 

.184601 

58° 

301 

9030 

451 

8579 

46473 

2 

.770 

.240 

.184800 










3 

.765 

.241 

.184365 

2 

t< 

.183840 

58 

307 

9210 

460 

8750 

47595 

4 

.765 

.241 

.184365 










5 

.760 

.243 

.184680 

3 

u 

.184560 

58 

320 

9600 

480 

9120 

49415 

6 

.762 

.240 

.182880 










7 

.763 

.240 

.183120 

4 

a 

.182960 

58 

328 

9840 

492 

9348 

51093 

8 

.763 

.240 

.183120 










9 

.762 

.235 

.179070 

5 

tt 

.183120 

58 

333 

9990 

499 

9491 

51283 

10 

,762 

.235 

.179070 










11 

.758 

.235 

.178130 

6 

(t 

,179070 

58 

341 

10230 

511 

9719 

54275 

12 

.761 

.235 

.178835 










13 

.764 

.235 

.179540 

7 

(4 

.178130 

58 

350 

10500 

525 

9975 

55997 

14 

.760 

.234 

.177840 










15 

.760 

.234 

.177840 

8 

44 

.177840 

58 

356 

10680 

534 

10146 

57028 

16 

.761 

.237 

.180357 


1834. 








17 

.762 

.237 

.180594 

9 

Jan. 18, 

.186885 

1159 

168 

5040 

252 

4788 

25620 

18 

.765 

.242 

.185130 










19 

.768 

.242 

.185856 

10 

May 31, 

.180555 

69.5 

319 

9570 

478 

9092 

50356 

20 

.767 

.245 

.187915 










21 

.762 

.241 

.183642 

11 

u 

.185454 

70 

347 

10410 

520 

9890 

53521 

22 

.764 

.235 

.179540 










23 

.765 

.240 

.183600 

12 

<( 

.186138 

70 

348 

10440 

522 

9918 

53571 

24 

.767 

.243 

.186381 










25 

.766 

.243 

.186138 

13 

u 

.186371 

70 

303 

9090 

454 

8636 

46212 

26 

.766 

.243 

.186138 










27 

.766 

.244 

.186904 

14 

u 

.185130 

70 

346 

10380 

519 

9861 

53265 

27^ 

.763 

.245 

.186935 










28 

.761 

.246 

.187206 


Mn. of 14= 

.183189 







Mean of 30 = 

.183338 










Maximum= 

.187915 










Miniraum= 

.177840 










Mean of the 2 .182877 










Diff. of the 2 

.010075 





i 







































143 


TABLE LVI. 

This strip. was cut in the direction across the sheet , reduced by filing 
jiom one inch in breadth and 4 inch in thickness , to the dimensions 
given below . Specific gravity 7.7428. 


Point of fracture. 

REMARKS. 

No 4£ 

C The first permanent elongation on this bar was observed under 210 

“ 1 

(. pounds. Part in the machine from 1 to 12. 

“ u 


“ 65 

A different piece from that broken in the preceding experiment. 

“ 8 


“ 9| 


“ 11 


“ 14 

C The 1st, 3d, 5th, 6th, 7th and 8th experiments give a decreasing 


C. series of areas with an increasing breaking weight. 

“ 194 

C Part in hot metal from 174 to 204, loaded with half the mean weight 


C required in the 8 preceding experiments. 

“ 224 


“ 23$ 


“ 25$ 


“ 194 

Short piece taken off by the wedges. 

“ 18 



The mean area of the 14 sections of fracture is .000149 square inch 


less than that of the 30 measured sections. 










144 

TABLE LVII. 


Experiments on bar No. 230. Manufactured by Messrs. E. T. Elli- 
cott Co., of Baltimore. The mode of manufacture, the source of the$ 


Marks. 

Breadth. 

Thickness. 

Area of the measured 
points before trial. 

No. of the experim’nt. 

DATE. 

Area of the section of 

fracture before trial. 

Temperature, Fah. 

Breaking weight in 

the scale. 

Breaking weight X 

leverage. 

Friction. 

0 

.760 

.250 

.190000 




J 




1 

.757 

.252 

.190764 








2 

.759 

.253 

.192027 


1834. 






o 

O 

.759 

.251 

.199509 

1 

June 28. 

.190509 

82° 

330 

9900 

495 

4 

.756 

.251 

.189756 








5 

.757 

.251 

.189907 








6 

.755 

.254 

.191770 








7 

.755 

.255 

.192525 

2 

if 

. 190373 

82 

330 

9900 

495 

8 

.753 

.255 

•192015 








9 

.756 

.255 

.192780 

3 

it 

.192270 

82 

334 

10020 

501 

10 

.755 

.254 

.191770 








11 

.755 

.254 

.191770 

4 

ft 

.192846 

82 

340 

10200 

501 

12 

.755 

.254 

.191770 








13 

.756 

.255 

.192780 

5 

if 

.191268 

82 

348 

10440 

522 

14 

.758 

.255 

.193290 








15 

.757 

.254 

.192278 

6 

if 

.192780 

82 

354 

10620 

531 

16 

.757 

.254 

.192278 








17 

.755 

.254 

.191770 

7 

if 

.192278 

82 

354 

10620 

531 

18 

.757 

.254 

.192278 








19 

.757 

.254 

.192278 

8 

ft 

.191833 

82 

361 

10830 

541 

20 

.755 

.254 

.191770 








21 

.756 

.253 

.191268 

9 

if 

.192024 

82 

363 

10890 

544 

22 

.756 

.251 

.189756 








23 

.756 

.253 

.191268 








24 

.757 

.253 

.190521 

10 

July 8, 

.190521 

75 

404 

12120 

606 

25 

.757 

.253 

.190521 








26 

.757 

.255 

.193035 








27 

.757 

.254 

.192278 

11 

it 

.192784 

75 

396 

11880 

594 

28 

.757 

.254 

.192278 








29 

.757 

.253 

.190521 

12 

it 

.191770 

75 

405 

12150 

607 

Mn. of 30 p’ts meas. 

.191584 

13 

ft 

.191770 

75 

405 

12150 

607 


Maximum 

.193290 

Mean of 13= 

=.191771 






Minimum .189756 
Mn. of these 2 .191523 
Diff. of the 2 .003534 











































145 


TABLE LVII. 

ore, the kind of pig-metal, fyc. not specified. This bar was cut lengthwise 
of the sheet. Specific gravity 7.6675. 


a 

E 


o 

*3 

o 

£ 

W 


9405 

9405 

9519 

9699 

9918 

10089 

10089 

10289 

10346 

11514 

11286 

11543 

11543 


Strength in lbs. per 
square inch. 

Point fractured. 

i 

49368 

No. 3 

49409 

“ 5f 

49508 

“ 7i 

50294 

“ 26* 

51849 

“ 21 

.52334 

“ 9 

52471 

“ 154 

53719 

“ 17* 

53879 

“ 19* 

60434 

“ 244 

58542 

“ 144 

60192 

“ 10 

60192 

« 12 


REMARKS. 


f First permanent elongation taken with 196 lbs. 

] Under 320 lbs., 26 inches had become 28.1, and 
after the fracture, the part from 3 to 25 was 24 
inches long. When the strain by 317 lbs. was re* 
Amoved the recoil on 24 inches was 1-20 of an inch. 
C The laminae are now distinctly visible along the 
s edge of the piece broken off, showing marks of 
Cpiling or lamellation. 


1 


C After this fracture, the part from 10 to 20 mea 
£ sured 11 inches. 


The piece now under trial, from 21 to 264, had 
been exposed to a strain of 386 lbs. for more than 
ten days, but showed no signs of yielding. 

This fracture took place almost within the gripe 


of the wedges. 


The mean area of the 13 sections of fracture is 
greater by .000187 square inch than that of the 30 
measured sections. 





















146 

TABLE LYIII. 

Comparative table showing the relative advantages of different modes oj manufacturing boiler-iron as 
deduced from preceding tables. 


\ 


Pro- 
cess of 

5 manu. 

Bars tried at original I 
sections. 

lars tried at deeply filed E 
sections. f 

iars reduced to a uni- T 
orm size by filing. 

J ames of the Ma¬ 

nufacturers. 

1 * 

o 

Jo. of 
the 
bar. 

strength 
of each 
bar. 

dn. st’h. I 
of the 
sets. 1 

'Jo. & 
of e 
>ar. 

»t’gth oft 
ach bar. s 

Mean 
trength. 
af sets, b 

No. 

of 

ar. 

strength 
of each 
bar. 

Vfn. st’h. 

of the 
sets. 


Piled f 
iron. 

1 

!}•« 
1 } ' 

32.421 

53.670 

33.045 


33.266 

< 

33.266 

3 ' 

36.081 

i 

36.081 

Mason St Milten- 
berger. 

2 Piled. 

25 

27 

30 

32 

35 

37 

39 

41 

46.079 

55.636 

44.703 

52.197 

43.237 

46.155 

40.595 

37.713 

45.914 







Shorb. 

3 Piled. 







226 

227 

228 

229 

230 

52.090 

53.774 
50.433 

55.774 
54.014 

53.217 

Evan T. Ellicott. 

4 Piled. 

242 

243 

59.247 

58.787 

59.017 







Valentine 

& 

Thomas, 

Ham- 
mer’d 
5 plate. 

9 

11 

17 

18 

21 

23 

58.243 

46.126 

44.249 

50.218 

39.578 

44.289 

47.117 

9 

10 

11 

13 

15 

22 

23 

67.211 ! 

64.511 

55.529 

50.908 

50.166 

59.372 

62.646 

58.620 

14 

16 

57.840 

56.891 

57.365 

Spang & Son. 

Ham- 
D mer’d 
plate. 

78 

81 

83 

84 

85 

87 

90 

43.006 
51.318 
49.23 9 
45.443 
51.606 
51.287 
43.365 

47.895 

75 

83 

85 

86 
90 

60.433 

56.046 

60.440 

62.156 

52.301 

58.275 

88 

53.803 

53.803 

Schoenberger. 

Ham- 
7 mer’c 
plate 

46 7 
48 5 

ll 

68 

70 

71 
73 

59.904 

61.091 

56.477 

61.127 

47.638 

64.823 

52.657 

57.676 




49 

59.607 

59.607 

Blake. 

Puc 
8 died 
iron. 

42 

44 

56 

58 

59 
61 

64 

65 

52.413 
54.718 
57.926 
53.112 
48.308 
55.904 
45.092 
51.25^ 

t 

l 

> 52.341 

56 

58 

60 

62 

65 

58.964 

70.938 

60.907 

58.376 

62.917 

62.42( 

74 

) 

51.039 

51.031 

Blake. 

) 

































































































































147 


Strength of Boiler Iron Manufactured by Different Processes. 

In making a comparison for determining this point, it was necessary to 
distinguish those experiments which were made on the strips as they came 
from the shears, from those which were performed on deeply filed sections, 
as well as from those in which the bars had been reduced to a uniform size. 

It is proper to observe, that the inherent irregularities of the metal, even in 
the best specimens, whether of rolled or hammered iron, seldom fall short of 
10 or 15 per cent., of the mean strength. 

Thus, of the bars referred to in the preceding table, No. 22 exhibits an 
irregularity of 19 per cent.; No. 23, 29 T 3 _, No. 90, 24; No. 230, 20 
t 8 q., and No, 228,31 percent, of the mean strength. These two last mentioned 
bars had been reduced to an uniform size and were entirely broken up at ordina¬ 
ry temperatures, chiefly with a view to the degree of uniformity of strength. 

It will be seen, on inspecting the preceding table, that of all the kinds of 
iron here presented, the piled iron of Mr. Shorb proved most defective in 
strength; some specimens of that kind, exhibiting, but little more than half 
as much tenacity as the best boiler iron which came under examination. 
Nos. 39, and 41, in particular, were found to possess extensive unwelded 
portions between the several laminae of the plate. 

These developed themselves to the distance of several inches when sub¬ 
jected to the action of the machine. 

In comparing the two kinds of iron manufactured by Messrs. Blake & Co. 
we find that the kind produced from blooms, and denominated hammered 
plate, is superior by about 13 per cent, to that manufactured by puddling. 

It will be observed that of the eight sets of results embraced in table 
LVIII., four, viz.: Nos. 1,5, 6, and 8 afford the means of comparing to¬ 
gether those trials which were made after all the three modes of preparing 
the bars. 

No. 1 gives to the rough bars a strength of 53045; to that which was re¬ 
duced to uniform size, 56081, and to those filed in notches on the edges, 
63266. In a similar manner finding for the other three sets their mean re¬ 
sults, we have for bars tried as they came from the shears, mean of four sets, 
50099 lbs; reduced to uniform size, 54572; for those filed on the edges, 60645. 

Strength of iron made by other processes than rolling into plates. 

The tables numbered from LIX. to LXXVIII. inclusive, will be found to 
contain the results of experiments on various specimens of iron manufactured 
by other processes than rolling into boiler-plate, particularly those of ham¬ 
mering into bars, slitting into rods, rolling into bolts and drawing into wires. 

In the number of specimens here tried the committee have included a few 
of foreign iron, Russian, Swedish and English, as well with a view to com¬ 
pare the results of their method of trial with those of former experimenters, 
as to show how far the processes generally adopted in manufacturing the 
article in this country may admit of improvement. 

A few experiments on boiler-iron, made upon original or on filed sections, 
will be found in Table LIX., and a small number of trials on cast iron, which 
does not, however, appear to have been of a very favourable character. Table 
LX. also contains accounts of a miscellaneous collection of specimens obtain¬ 
ed from different quarters. The remaining tables in this series relate to bars 
which had been reduced to approximate uniformity of size throughout their 
whole length, and not a few of them were tried at elevated as well as ordi¬ 
nary temperatures ; but of the former we shall speak more at length in a sub¬ 
sequent part of this report. 


IS 


148 

TABLE LIX. 

Experiments on bars No. 99 , 101 , 103 , 105 , 180 , 181 , 182 and 185 . Thefrst two manufactured by Pennock 7 
into boiler plate ;tlie next two by Jackson into the same article , and the remaining numbers obtained from $ 


No. of the bar. 

Direction of the 
slit. 

No. of the exp. 

DATE. 

Length before 

trial. 

Breadth. 

Thickness. 

Area of the sec¬ 

tion of fracture 
before trial. 

Teir.p. Fah. 

Breaking wht. 

in the scale. 

Breaking wht. 

X leverage. 

Friction. 

Effective strain. 

0» 

£ 

.2 . 

X, 
x « 
c 
6C.S 

X • 

<v c r 

i/i 

+* . 

W z 
a. 




1832. 











99 

Cross. 

1 


24.3 

1.016 

.214 

.217424 

62.25 

378 

11340 

567 

10773 

* 

49548 

101 

L’gth. 

2 


25.1 

1.014 

.230 

.233220 

62.5 

403 

12090 

604 

11486 

49258 

101 

u 

3 



.826 

.240 

.198240 

62.5 

384 

11520 

576 

10944 

55206 

103 

Cross. 

4 


23.8 

1.038 

.190 

.197220 

62.25 

321 

9630 

481 

9149 

41319 

103 

U 

5 

May 30, 

9.6 

.984 

.200 

.196800 

67. 

361 

10830 

541 

10289 

52281 

105 

L’gth. 

6 

Ap. 28, 

24.2 

1.050 

.196 

.205800 

62.5 

322 

9660 

483 

9177 

44591 

105 

a 

7 



1.045 

.196 

.204820 

62.5 

345 

10350 

517 

9833 

48068 


On a bar of slit iron hammered out , having two sections much smaller than the rest but equal to each 


180 


-o 

o> 


© 

S -TJ © 

e w 
S « ~ 

cd ^ 

X 


8 


10.25 


.882 


.216 


.190512 


60. 


324 


9720 


486 


9234 


48469 


On a bar of cast steel furnished by Mr. R. Tyler in which were trivo equal square sections. 31 of an inch 


181 


Cast 

steel. 


,310 


,310 


,096100 


65. 


441 


13230 


661 


12569 


130681 


182 

Rolled 
& slit. 

10 

|23.5 

.980 

.254| .248920 

65. 

455 

13650 

682|l2968 

52096 


On a bar of cast iron obtained from the foundry of Messrs. Levi Morris & Co. Philadelphia 


185 

185 

185 


Cast 

iron. 


11 

12 

13 


24. 

19.2 


1.032 

.280 

.288960 

69. 

196 

5880 

294 

5586 

19337 

1.054 

.280 

.295120 

69. 

210 

6300 

315 

5985 

20279 

1.056 

.250 

.264000 

69. 

212 

6360 

318 

6042 

22886 


















































































































149 

i 

TABLE LIX. 

different quarters, as specified below. Specific gravities not taken. 


Weights produ¬ 

cing temporary e- 
lon oration. 

Elasticity of the 

bar. 

1 

Length after tri¬ 

al. 

Area of the sec¬ 

tion after trial. 

REMARKS. 

< 

f224 
J 336 
) 378 
1378 

20 ' ''i 

36 1 

42 

Broke. J 

> 24.45 

Cl.010x.204 7 
l =.206040 5 

Broke under 378 lbs. after the elasticity 
had been observed. Gave way suddenly. A 
small scale or flaw appeared on one side of 
the section of fracture. 

; 

C224 
< 336 
'403 

35 •) 

41 e 

Broke, j 

25.3 

C .986X.2107 
l =.207060 3 

C .821 x. 196 7 
l =.160916 3 

Broke at the filed section. 

< 

i 

("224 
280 
308 
L321 
{ 168 
1361 

38 

34 l 
43.5 f 
Broke. J 
07. 7 

Broke. 3 

- 24.09 

9.8 

C1.014X.1747 
l X-176436 3 

C . 942 X *152 7 
l =.143184 3 

1 


f224 

294 

320 

^322 

1.03 -3 
1.04 1 

1.03 f 
Broke. J 

[24.45- 

C1.024X.180 7 
l =.184320 3 

Broke near the wedges. 

* The length after fracture is that of the whole bar after 
both trials. 

other-, l 

he one upset 

-the othe 

10.86 

r not. Furnished by 

Mr. Rufus Tyler. 

^ Direct measurements were taken to ascer¬ 
tain the recoil of the bar when relieved from 
strain under different whts. With 2241bs. 

J the length was 10.40 when the weight was 
j applied; butonly 10.366 when it was taken 
off.—With 250 lbs. it was 10.50 and 10.45 
in the two cases; and with 273 lbs. 10.62 
^andl0.60. Broke at the section not upset. 

or 

< 

a sid 

'"112 

224 

336 

385 

406 

415 

422 

429 

441 

", the one uf 

20.5 "A 
30 . 

28 . 

36.5 

40.5 V. 

39.5 c 

36.5 

37.5 

Broke. J 

set—the 

other not. 

C .840X.1907 
l =.159600 3 

Broke at the upset part. 

| 


25.661 

1 


ri68 
(_ 196 

C 189 
(210 

37 7 

Broke. 3 

35 7 

Broke. 3 


• 

1 

c 

A filed section was made;-its area 1.018 X 
230=.234140. Broke suddenly with the 
weight recorded—filed section not broken. 

Do. 

It was found difficult to make the wedges 
iold the cast bars so as to equalize the strain. 

The filed section remains unbroken and has 
)f course borne 25.762 lbs. to the sq. inch. 






















































150 


TABLE LX. 

Experiments on a variety of specimens of iron , furnished by different 



d 






(■" • 

—• 

C rt 


.2 

X 




2 






'•£ u 



■*-> 




4 ) 






o 

a J> 


pC 

to 

'So 


2 

s 

c* 

2 

2 


P- 

X 

0 

0 

.o 



£<2 

r— 

• 

• p«* 

0 

p 

£ 


"cS 

4 -> 

0 

■*-> 

0 - 

O 

o 

a 

g 

0 -. 

o 

0 

o 

DATE. 

0 

pC 

■+-> 

0 * 

o 

o 

CP 

0 

pP 

pP 

•*-> 

fcjO 

P 

0 

CJ 

V 

t* 

f/) 

(/i 

o 

c 

4 ) 

12 

^ pP 

0 * 0 
o t- 
2 
a 

£ S* 

C. 

£ 

3 

iC 

.Zjj 
a & 

Qj O 

t, «« 

Breaking 

everage. 

2 

.2 

■*-* 

0 
• H 

C/3 

0 

*2 

o 

f 0 

fa 

£ 

s 


jz; 

1-1 

« 

h 

0 * 

h 

PQ ^ 

pP 

Ph 

£ 















On a bar furnished by Mr. R. Tyler, in which was a section annealed at a 

9291 


191 


Ham. & 
annealed 


15. 


.880 


.220 


.193600 


68 


326 


9780 


489 


Oi 

Furn 

215 

a small ) 
ished by 

Rolled 
into rail. 

■ailroad b< 
Jerard Ra 

ir o 

1 st 

2 

f English 
on, Esq. o 

.740 

“con 
f Phi 

.262 

imon iron 
ladelphia. 

.193880 

in 

81 

whin 

412 

i a dee^ 

12360 

sectic 

618 

)n had 

11742 

Or 

217 

i a rod of 
Puddled, 
pil. & rol. 

round iror 

i m 

3 

ade from t 
|Diam. 

1.660 

he pi 

Diam. 

.660 

g, by puddling 

.342120| 68 

pilir 

700 

g, and 

21000 

then rc 

1050 

oiling, 

19950 


On specimens of Juniata iron, both hammered and slit. Furnished by Mr. G. 


234 

Hamm’d. 

1833. 
May 18, 

4 


.357 

.357 

.127449 

77 

254 

7620 

381 

7239 

234 

U 

U 

5 


.300 

.382 

.114600 

77 

209 

6270 

313 

5959 

234 

u 

(C 

6 


.368 

.382 

.140576 

77 

273 

8190 

409 

7781 

235 

Rolled & 
slit. 

u 

7 


.300 

.295 

.088500 

77 

196 

5880 

294 

5586 


On a small bar furnished by Messrs. Yeatman & Woods, of Nashville, Tenn. 


236 


Rolled. 


U 


8 


.324 .392 


127008 


77 


231 


6930 


346 


6584 


On a bar ot rolled and slit iron, manufactured with coke, and reduced by pud- 
Susquehanna, Pa. 

1836. 


244 


Rolled 
&. slit. 


Mar. 21. 


4.5 


o o >7 

.00/ 


.253 


.085261 


50 


209 


6270 


313.5 


5856,5 


I 














































































































151 


TABLE LX. 


individuals , as mentioned below. Specific gravity not taken. 


Strength in lbs. per 

square inch. 

Length after trial. 

Area of section after 

trial. 

REMARKS. 

weldinj 

47991 

g heat. 

16.42 

• 

C.766X.156 } 
£=.119496 5 

r Broke at the annealed part. Began to be per- 
J manently elongated with 210 lbs. and continued to 
i extend with the successive additions of weight 
kuntil broken. 

been fi] 

60563 

ed, the bar being orig 

1 

! 

1 

•inally an inch wide and one-third of an inch thick. 

C This section was so deeply filed as to remove 
£ all probability of a defect in the remaining section. 

without any ot 
58313] 

her operation for r 

•efiningthe metal. Furnished by Jonah Thompson, Esq. 

Valenti 

56799 

51981 

55351 

63119 

ne, of 

Centre county, 

Pennsylvania. 

51839 





Rltner, Esq., Carthause’s place, West Branch of the 

Fracture granular, with much crystalline structure. 
A yellowish tinge perceptible in certain parts. 

! 

Q- 

eg =» 

8 °5 

o 

Furni 

shed by Peter 

i 


13 * 






































152 


TABLE LXI 

Experiments on bars No. 212 and 213, drawn out of a specimen oj" 
English bolt iron lg inches in diameter, presented by G. Ralston, Esq., 
described as, “ E. V. best patent cable bolt iron.” The specimen had \ 
been formed into a knot when cold, by means of a pair of pincers. The J 


Marks. Bar 213. 

Breadth. 

Thickness, 

Area of the sections 
measured before trial. 

No. of the experiment. 

DATE. 

Area at the section of 
fracture. 

Temperature, Fah. 

Breaking weight in 

the scale. 

Breaking weight X 

leverage. 

% 

Friction • 

Effective strain. 

Strength in pounds per 

square inch. 

j 

1 

.741 

.239 

.177099 


1833. 


o 






2 

.743 

.236 

.175348 

1 

July 20, 

.175171 

560 

364 

10920 

546 

10374 

59222 

3 

.743 

.236 

.175348 










4 

.743 

.236 

.175348 

2 

tc 

.175348 

80 

366 

10980 

549 

10431 

59487 

5 

.742 

.236 

.175112 










6 

.743 

.236 

.175348 

3 

July 25, 

.175348 

84 

410 

12300 

615 

11685 

66639 

7 

.743 

.235 

.174605 










8 

.744 

.235 

.174840 

4 

(t 

.174976 

80 

436 

13080 

654 

12426 

71015 

9 

.742 

.236 

.175112 










10 

.744 

.236 

.175584 

5 

6« 

.174859 

78 

439 

13170 

658 

12512 

71555 

11 

.744 

.236 

.175584 










12 

.744 

.236 

.175584 

6 

t( 

.175128 

78 

437 

13110 

655 

12455 

71119 

13 

.744 

.239 

.177816 










14 

.741 

.238 

.176358 

7 

a 

.173628 

78 

437 

13110 

655 

12455 

71734 

15 

.742 

.237 

.175854 










16 

.741 

.237 

.175617 

8 

44 

.177162 

78 

437 

13110 

655 

12455 

70303 

17 

.743 

.238 

.176834 


• 








18 

.740 

.236 

.174640 

9 

u 

.175617 

78.5 

437 

13110 

655 

12455 

70921 

19 

.740 

.236 

.174640 










20 

.744 

.239 

.177816 

10 

44 

.175434 

78. 

435 

13050 

652 

12398 

70670 

21 

.742 

.237 

.175854 










22 

.742 

.234 

.173628 

11 

44 

.175795 

77.5 

436 

13080 

654 

12426 

70685 

23 

.742 

.235 

.174370 










24 

.743 

.236 

.175348 

12 

it 

.176358 

78. 

439 

13170 

658 

12512 

70947 

25 

.740 

.236 

.174640 










26 

.741 

.237 

.175617 

13 

(C 

.175584 

78. 

439 

13170 

658 

12512 

71265 

27 

.741 

.236 

.174876 















Mn. of 13 = 

.175416 







Mean of 27= 

.175512 

Ex] 

>eriment on 












No. 2i2, part of 












the same bolt. 









Maximum 

.177816 

Br. Th. 









Minimum 

.173628 

1.041 | .256 

.268496 

82 

565 

16950 

847 

16103 

59975 

Mean of the 2 

.175722 










Diflf. of the 2 

.004188 
























































153 


TABLE LXI. 


< 


fexterior dimensions of the knot were 5 1 by Scinches. After heating 
j and untieing this knot the bar was drawn out by the hammer. No. 213 was 
reduced to a nearly uniform size by /ding, and then gauged at every inch , 
'rom 1 to 27 inches. No. 212 tried at a filed section. Sp. grav. 7.6897. 


L/ J 


6 

u 

P 

+-> 

o 

C3 

Im 

o 

g 

*3 


REMARKS. 


< 0 . 


i. 


u 


4# 

3 

94 


Part in tin from 5 to 8. The influence of the heat at this tempera¬ 
ture was made to extend to all parts of the bar—with a view to ascer¬ 
tain whether any points of inferior strength could be thereby detected— 
but the structure appears to have been remarkably uniform, as seen in 
subsequent trials. 


it 


64 


“ 234 
“ 254 
“ 22 


“ 204 


“ 16 


“ 194 
“ 154 
“ 14 


“ 12 


The mean area of the 13 sections of fracture is .000096 square inch 
less than the mean area of the 27 measured sections. 


This fracture made on a filed section. 












« 


154 

TABLE LXII. 


Experiments on bar No. 214, drawn out of a specimen (the same with1 
213 ) of English cable bolt iron, 1§ inches in diameter , presented by G. v 
Ralston, Esq., described as “ E. V. best patent cable bolt iron.” The j 


Marks. 

43 

w 

a 

V 

u 

eq 

Thickness. 

Area of section at the 
points measured. 

1 

DATE. 

*■« 

.5 

3 

SL 

* 

V 

+-> 

<*- 

o 

© 

£ 

Area of the section of 

fracture before trial. 

Temperature. Fah. 

Breaking weight in 

the scale. 

Breaking weight X 

leverage. 

d 

# o 

’w 

O 

Effective strain. 

Strength in lbs. per 

square inch. 

1 

.752 

.239 

.179728 

1833. 









2 

.751 

.237 

.177987 

July 27, 

1 

.177750 

83° 

354 

10620 

531 

10089 

56759 

3 

.750 

.237 

.177750 










4 

.750 

.237 

.177750 










5 

.750 

.239 

.179250 

66 

2 

.178066 

83 

370 

11100 

555 

10545 

59219 

6 

.750 

.239 

.179250 










7 

.750 

.239 

.179250 










8 

.749 

.239 

.179011 










9 

.750 

.241 

.180750 










10 

.749 

.341 

.180509 




r QO/1 ^ 






11 

.749 

.241 

.180509 

66 

3 

.180509 

V OZ*± J 

) Q1M 

354 

10620 

531 

10089 

55892 

12 

.749 

.241 

.180509 










13 

.749 

.239 

.179011 










14 

.747 

.238 

.177786 










15 

.752 

.239 

.179728 

66 

4 

.179250 

81 

408 

12240 

612 

11628 

64870 

16 

.751 

.240 

.180240 










17 

.750 

.239 

.179250 

66 

5 

.180690 

82 

434 

13020 

651 

12369 

68454 

18 

.749 

.239 

.179011 










19 

.748 

.240 

.179520 










20 

.750 

.239 

.179250 

66 

6 

.179130 

932 

283 

8490 

424 

8066 

45029 

21 

.750 

.240 

.180000 










22 

.748 

.241 

.180268 










23 

.749 

.240 

.179760 










24 

.749 

.240 

.179760 










25 

.752 

.240 

.180480 

66 

7 

.179760 

1022 

236 

7080 

354 

6726 

37410 

26 

.752 

.241 

.181232 










27 

.752 

.238 

.178976 










Mean of 27 .179501 

Aug. 1, 

8 

.179760 

80 

294 

8820 

441 

8379 

46612 


Maximum 

.181232 

66 

9 

.180141 

80 

383 

11490 

574 

10916 

60597 


Minimum 

.177750 

66 

10 

.179393 

80 

383 

11490 

574 

10916 

60850 




— 

66 

11 

.180240 

80 

362 

10860 

543 

10317 

57240 

Mn. of these 2 

.179491 

66 

12 

.180856 

80 

380 

11400 

570 

10830 

59882 





66 

13 

.179745 

80 

377 

11310 

565 

10745 

59779 

Diff. of the 2 

.003482 

66 

14 

.180069 

80 

392 

11760 

588 

11172 

62043 





66 

15 

.178092 

80 

401 

12030 

601 

11429 

64175 





Mean of 15 

.179563 





1 











































155 


TABLE LXII. 

f bar reduced by hammering and filing to uniform size , and then gaug - 
•j ed at every inch from 1 to 27. Specific gravity , 7.6897. 


r3 

c3 


cq 


& 

•s 

5 


a> 


.623 


.563 


196 


174 


.603 


.185 


cS 

*2 


ci 

a> 


.122108 


099651 


111555 


p 

3 

O 

«S 


o 


o 

Ph 


No. 


<< 


a 

ti 

it 

it 

is 

a 

it 


O Q 


91 

^3 


“ 10i 


<« 


*( 


<« 


64 


94 


174 


23# 


23# 

224 

18# 

24# 

254 

164 

15# 

13# 


REMARKS. 


A 


l 


< 


f Short piece broken off in the preceding experi¬ 
ment. These two experiments were made on the bar 
when cold , with a view to get the approximate te¬ 
nacity in that state. 

Having placed in the scale the same weight as 
was used in the first experiment, the temperature 
was raised, by means of the moveable furnace, to 
such a point that the bar was rapidly giving way. 
The standard piece was withdrawn and tried twice, 
giving, successively, the temperatures marked. 

Part now in the machine from 3# to 104 


Same part under trial as in the preceding exp’t. 

The scale was now loaded with four-fifths of the 
breaking weight in the first experiment. The dif¬ 
ference of areas caused an excess of 452 lbs. above 
four-fifths of the strength exhibited in that experi¬ 
ment. Bar not actually parted. 

Part in tin from 22 to 25. The weight employed 
# of that used in the first experiment. Section 
larger, hence the strength is 978 lbs. less than # 
of 56759. The length from 23 to 24 was now 
4.1.46 in. Not actually parted. 

C The same section as that tried in the preceding 
L experiment. 


< 


1 


The mean area of 15 sections of fracture is .000062 
square inch greater than the mean area of the 27 
measured sections. 


























156 


TABLE LXIII. 

Experiments on bars No. 213a and 214a, taken respectively from bars 
213 and 214. Reduced by hammering and filing to a nearly uniform 


VI 

X 

Sh 

s 

Breadth. 

Thickness. 

Area before trial at the 
points measured. 

No. of the experiment. 

DATE. 

Area of the section of 

fracture before trial. _ 

Temperature Fahren¬ 

heit. 

Breaking weight in’tlie 

scale. 

Breaking weight X 

leverage. 

Friction. 

Effective strain. 



213 

a 









1 

.748 

.230 

.172040 









2 

.746 

.230 

.171580 

1 


.171580 

78 

396 

11880 

594 

11286 

3 

.747 

.232 

.173304 









4 

.747 

.229 

.171063 









5 

.747 

.229 

.171063 

2 


.170949 

78 

421 

12630 

631 

11999 

6 

.745 

.229 

.170605 









7 

.745 

.230 

.171350 









8 

.745 

.230 

.171350 

3 


.170605 

78 

431 

12930 

646 

12284 

9 

.745 

.230 

.171350 










Mean of 9 .171534 

4 


.170977 

78 

431 

12930 

646 

12284 


Maximum .173304 


Mn. of 4 = 

.171028 







Minimum 

.170605 









Mn. of the 2.171954 









Diff. of the 2 .002699 











214a 









1 

.750 

.226 

.169500 









2 

.747 

.225 

.168075 

1 


.169231 

80 

410 

12300 

615 

11685 

3 

.743 

.225 

.167175 









4 

.743 

.228 

.169404 


- 







5 

.744 

.228 

.169632 

2 


.169518 

80 

412 

12360 

618 

11742 

6 

.739 

.226 

.167014 









7 

.739 

.227 

.167753 









8 

.739 

•227 

.167753 

3 


.168246 

84 

443 

13290 

664 

12626 

9 

.739 

.229 

.169231 









10 

.739j 

.228 

.168492 













4 


.168966 

84 

438 

13140 

657 

12483 

Mean of 10.168402 














Mn. of 4 — 

.168990 







Maximum 

.169632 










Minimum 

.167014 









Mn. of these 2.168323 









Diff. of the 2 .002618 












































157 


TABLE LXIII. 

size , and then gauged at every inch. These bars were both hammered 
until cold , technically “ hammer-hardened 


Strength In lbs. per 
sq. inch. 

Point of fracture. 

REMARKS. 

\ 

• 

65718 

No, 2 


70190 

“ 5J 


72002 

“ 6 


71845 

“ 6^ 

The mean area of these 4 sections of fracture is .000506 square 
inch less than the mean area of the 9 measured sections. 

69047 

“ 9 


69267 

“ H 


75045 

“ 8J 


73879 

“ If 

The mean area of these 4 sections of fracture is .000498 square 
inch greater than the mean area of the 10 measured sections. 





















158 


TABLE LXIV. 


Experiments on a specimen of iron wire. Manufactured at Phil- 
process of manufacture, refining, fyc. not stated. 


No. of the bar. 

Mode of manufacture. 

DATE. 

Number of the ex¬ 

periment. 

Diameter before trial. 

Area of section be¬ 

fore trial. 

% 

Temperature. Fall. 

Breaking weight in 

the scale. 

Breaking weight X 

leverage. 

Friction. 

199 

Wiredrawn. 


1 

.333 

.0870922 

550° 

246 

7380 

369 

199 

it 


2 

.333 

it 

66 

253 

7590 

379 

199 

u 


3 

.333 

a 

66 

257 

7710 

385 

199 

u 


4 

.333 

it 

66 

257 

7710 

385 

199 

a 


5 

\ 

.333 

u 

66 

257 

7710 

385 

199 

tt 


6 

ooo 
• OuJ 

« 

60 

258 

7740 

387 

199 

tt 


7 

.333 

a 

50 

270 

8100 

405 

199 

tt 


3 

.333 

a 

50 

221 

6630 

331 

199 

tt 


9 

.333 

tt 

60 

236 

7080 

354 

199 

tt 


10 

.333 

« 

450 

242 

7260 

363 

199 

a 


11 

.333 

tt 

60 

249 

7470 

373 

199 

4€ 


12 

.333 

tt 

60 

241 

7230 

361 

199 

it 


13 

.333 

<< 

60 

243 

7290 

364 



























159 


TABLE LXIV. 

lipsburg, Pennsylvania , by Mr. Hardman Phillips , from Juniata iron , 


Effective strain. 

Strength in lbs. per 
square inch. 

Area of section after 
trial. 

REMARKS. 




The specific gravity of this wire was 7.7272. 

7011 

80501 



7211 

82797 

C. 240 X. 240 X- 7854-) 
l =.045239 5 

"■ Only two measurements of area after 
fracture are recorded, but others were oc¬ 
casionally taken, all agreeing very nearly 
. with these, and exhibiting a uniform dimi- 
^ nution in all directions, and a remaining 
section almost precisely one-half as great 
as the original transverse section of the 
Lwire. 

7325 

84106 



7325 

84106 


t 

7325 

84106 



7353 

84427 



7695 

88354 



6299 

72325 



6726 

77228 



6897 

79192 



7097 

6869 

81488 

78870 

C. 234 X- 234 X- 7854^ 
l =.0430132 5 

■ 

6926 

79524 




14 




















160 


TABLE LXV. 

Experiments on bar No. 223 A. From Missouri. Manufactured by 
Mr. Massey , at the Maramec Iron Works. Drawn under the hammer 


Marks. 

Breadth. 

C f) 

V) 

ZJ 

j-1 

Area of sections mea¬ 
sured before trial. 

No. of the experiment. 

DATE. 

Area of section at the 

point of fracture before 

trial. 

Temp. Fah, 

Breaking wht. in the 

scale. 

Breaking weight X 

leverage. 

3 

.o 

V 

Effective strain. 

Strength in lbs. per 

sq.inch. 

0 

.761 

.230 

.175030 


1833. 








1 

.758 

.230 

.174340 

1 

May 2, 

.175180 

80 

269 

8070 

403 

7667 

43766 

2 

.758 

.232 

.175856 










3 

.758 

.230 

.174340 

2 

66 

.174685 

80 

281 

8430 

421 

8009 

45896 

4 

.758 

.230 

.174340 










5 

.756 

.230 

.173880 

3 

it 

.174867 

79.5 

281 

8430 

421 

8009 

45556 

6 

.757 

.231 

.174862 










7 

.758 

.231 

.175098 

4 

tt 

.175972 

79.5 

281 

8430 

421 

8009 

45513 

8 

.756 

.232 

.175392 










9 

.759 

.232 

.176088 

5 

tt 

.175098 

79.5 

294 

8820 

441 

8379 

47853 

10 

.758 

.232 

.175856 


1834. 








11 

.759 

.232 

.176088 

6 

May 4, 

.175307 

570 

309 

9270 

463 

8807 

50238 

12 

.760 

.232 

.176320 










13 

.760 

.231 

.175560 










14 

.760 

.230 

.174800 

7 

tt 

.174845 

578 

328 

9840 

492 

9348 

53465 

15 

.760 

.232 

.176320 










16 

.759 

.231 

.175329 










17 

.759 

.229 

.173811 

8 

66 

.174665 

65 

363 

10890 

544 

10346 

59233 

18 

.759 

.230 

.174570 










19 

.758 

.232 

.175856 










20 

.758 

.230 

.174340 

9 

tt 

.173250 

65 

354 

10620 

531 

10089 

58239 

21 

.758 

.231 

.175098 










22 

.758 

.232 

.175856 










23 

.758 

.232 

.175856 

10 

66 

.175856 

65 

358 

10740 

537 

10203 

58018 

24 

.758 

.232 

.175856 










25 

.756 

.232 

.175392 

11 

66 

.175477 

65 

358 

10740 

537 

10203 

58144 

26 

.755 

.231 

.174405 










26^ 

.750 

,231 

.173250 


Mil. of 14 = 

.175018 








Mean of 28 .175135 


Maximum . 176320 
Minimum . 173250 


Mean of the 2.174785 
Diff. of the 2.003070 










































161 


TABLE LXV. 


and then reduced by filing and gauged at points 1 inch apart. Specific 
gravity 7.7708. t i J 


hp 

S 

o 
S3 
1 B 
O 

C. 


JS C 
bo O 


> 




168 

224 

252 

269 


fcX) 

S 

Cm 

O 


<v) 

0) M 

O £ 


1st permanent. 
. 3 inch. 

• 7 do. 

Broke. 


0> 

u 


a 

* 


o 

& 


No.l3£ 


“ 0* 


u 


“ 9* 


REMARKS. 


<« 


2 i 


(« 


144 


“ 19# 


“ 18# 


“ 26^ 


“ 23# 
“ aii 


Weights not altered. 

Do. 

Part in tin from 18 to 22. 


Broke in the melted tin—part in the metal, same as 
in the preceding experiment. 


A different piece from the preceding—had been 
most remote from the melted metal, fracture diagonal. 

Had not been in tin. 

A flaw about the middle of the thickness now ap¬ 
peared,—This bar exhibited more than any yet tried, 
a dull recoil only, when it finally gave way, as if the 
elasticity had been almost totally destroyed. 

The mean area of the 11 sections of fracture is 
000117 square inch less than that of the 28 measured 
sections. 


















162 


TABLE LXVI. 


Experiments on bar No. 223 B. From Missouri. Manufactured by 
Mr. Massey , at the Maramec Iron Works , drawn under the hammer. 




CD 

CD 

>> 

w 

r, o 

a 

© 

<y 

£ 

n 

'-a 

h 

1 

.764 

.239 

2 

.755 

.240 

3 

.755 

.240 

4 

.755 

.239 

5 

.755 

.238 

6 

.755 

.239 

7 

.755 

.238 

8 

.755 

.236 

9 

.752 

.236 

10 

.753 

.236 

11 

.753 

.238 

12 

.755 

.239 

13 

.755 

.238 

14 

.755 

.239 

15 

.755 

.239 

16 

.755 

.240 

17 

.755 

.239 

18 

.755 

.240 

19 

.756 

.238 

20 

.756 

.237 

21 

.756 

.239 

22 

.755 

.240 

23 

.755 

.240 

24 

.753 

.240 

25 

.755 

.240 

26 

.755 

.240 

27 

.760 

.240 

27i 

.762 

.240 


DATE. 

No. of the exp’t. 

Area of the section 

of fracture before trial. 

Temperature, Fall. 

Breaking weight in 

the scale. 

Breaking weight X 

leverage. 

Friction. 

■*-» 

CO 

© 

> 

9 

,V 

S2 

1833. 








May 9, 

1 

.179690 

76 

262 

7860 

393 

7467 

“ 

2 

.181041 

76 

270 

8100 

405 

7695 

« 

3 

.179172 

76 

271 

8130 

406 

7724 

« 

4 

.180960 

76 

277 

8310 

415 

7895 

« 

5 

.181200 

76 

284 

8520 

426 

8094 

u 

6 

.180445 

76 

284 

8520 

426 

8094 

1833. 








May 11, 

7 

.178180 

576 

313 

9390 

469 

8921 


8 

.180445 

70.5 

336 

10080 

504 

9576 


9 

.182596 

70.5 

322 

9660 

483 

9177 


10 

.180067 

70.5 

347 

10410 

520 

9890 

<< 

11 

.179690 

70.5 

347 

10410 

520 

9890 

Mean of 11 .180317 







51 

c z £ 

I’S 

w U 
V 2 

Oj CD 
v) oj 

O g 

QJ CD 

*< .5 cs 
©•r 


.182596 

.181200 

.181200 

.180445 

.179690 

.180445 

.179690 

.178180 

.177472 


Mean of 28= .180439 


Mn. of these 2 .180176 


Diflf. of the 2 .005408 






































163 


TABLE LXVI. 

reduced by filing , and gauged at points one inch apart. Specific 
gravity , 7.6742. 


Strength in lbs. per 
square inch. 

Point fractured. 

REMARKS. 

- 


f Under a weight of 245 lbs. in the scale the elongation had 



| become .85 inch in 22 inches. The breadth at No. 13 was 

41555 

No. 13 

J then .718, diminution .037. After this experiment 12 inches 



j on one side of the fracture, as originally measured, were found 



| to have been elongated to 13^, and 10 on the other to 11 1-20, 



^exhibiting an extension of 2.55 in 22 inches. 

42504 

“ 18* 

- 

43109 

“ 20 


43628 

“ 2 3* 


44669 

“ 2 51 


44855 

“ 14* 


50068 

« 8 

Part in tin from to 10. 

53069 

“ 12 

Part now under trial from 8 to 13. 

50258 

« 1 

r Broke soon after applying the weight. Part now under 



£ trial from 1 to 8. 

54924 

« 

Broke quickly with this weight. 

55039 

“ 5 




The mean area of the 11 sections of fracture is .000122 sq. 



inch less than the mean area of the 28 measured sections. 


14 * 




















164 


TABLE LXV1I. 

Experiments on bar No. 223 C. Manufactured at the Maramec 
Iron Works, Missouri, by Mr. Massey, drawn under the hammer, re- 5 


Marks. 

Bieadth. 

Thickness. 

A rea before trial. 

No. of the exp’t. 

DATE. 

Areas of section of 

fracture before trial. 

Temperature, Fah. 

Breaking weight in 

the scale. 

Breaking weight X 

leverage. 

Friction. 

Effective strain. 

1 

.741 

.243 

.180063 


1833. 


o 





3 

.751 

.242 

.181743 

1 

May 11, 

.180870 

576 

282 

8460 

423 

8037 

2 

.748 

.242 

.181016 









4 

.751 

.242 

.181742 

2 


.181232 

578 

308 

9240 

462 

8778 

5 

.751 

.242 

.181742 









6 

.751 

.240 

.180240 

3 

44 

.182178 

578 

329 

9870 

493 

9377 

7 

.751 

.241 

.180991 









3 

.751 

.242 

.181742 

4 

May 16, 

.181742 

550 

338 

10140 

507 

9633 

9 

.751 

.240 

.180240 









10 

.751 

.240 

.180240 

5 

it 

.180870 

550 

331 

9930 

496 

9434 

11 

.751 

.242 

.181742 









12 

.751 

.242 

.181742 

6 

44 

.179545 

78 

364 

10920 

546 

10374 

13 

.751 

.242 

.181742 









14 

.751 

.242 

.181742 

7 

u 

.179301 

78 

365 

10950 

547 

10403 

15 

.751 

.242 

.181742 









16 

.751 

.243 

.182493 

8 

(4 

.178738 

78 

371 

11130 

556 

10574 

17 

.752 

.241 

.181232 









18 

.752 

.241 

.181232 

9 

(4 

.180991 

78 

372 

11160 

558 

10602 

19 

.751 

.241 

.180991 









20 

.749 

.241 

.180509 

10 

May 18, 

.181742 

78 

369 

11070 

553 

10517 

21 

.752 

.241 

.181232 









22 

.751 

.239 

.179489 

11 

44 

.181379 

78 

369 

11070 

553 

10517 

23 

.751 

.238 

.178738 


* 







24 

.750 

.242 

.181500 

12 

(4 

.181492 

78 

369 

11070 

553 

10517 

25 

.751 

.241 

.180991 









26 

.751 

.241 

.180991 

13 

44 

.181742 

78 

371 

11130 

556 

10574 

27 

.748 

.242 

.181016 









27.25 

.745 

.241 

.179545 

14 

44 

.181742 

78 

371 

11130 

556 

10574 

Mean of 28 .181015 


Mean of 14 

.180968 







Maximum .182493 
Minimum .178738 


Mean of the 2 .180615 
Differ, of the 2 .003755 

































165 


TABLE LXVI1, 

duced by filing, and gauged at every inch. Specific gravity 7.7708. 





0 . 



m 

6 



B 


• m 

fC pC 

a 

& 

REMARKS. 

ti>s 

fl.- 

o 

w 


U g 
uri § 
u* 

VI 

*3 


44435 

No. 20^ 

The whole length of the bar was put under trial. The part 
in tin from 5£ to 9. 

48435 

“ 18 

Same part in tin as above. 

51713 

“ 16i 

Same part in tin. This fracture is at the largest section in 
the bar. 

53004 

“ 2 

The same part still in tin. 

52158 

“ 2H 

Part in tin from 22 to 26. Broke at a place previously in the 

gripe of the wedges. 

57779 

“ 27-?c 


58020 

“ 22i 


59159 

“ 23 


58577 

“ 25£ 


57879 

“ 13* 


57983 

“ 2* 


57947 

“ 7$ 


58181 

“ 11 


58181 

“ 4 

The mean area of the 14 sections of fracture is .000047 square 



inch less than that of the 28 measured sections. 












166 


TABLE LXVIII. 

Experiments on bar No. 223 D. From Missouri. Manufactured by ) 
Mr. Massey , at the Maramec Iron Works , drawn under the hammer 5 


Marks. 

Breadth 

Thickness. 

Areas at the points 

gauged. 

No. of the experiment. 

DATE. 

Area at the point of 

fracture. 

Temperature Fahren¬ 

heit. 

Breaking weight in the 

scale. 

Breaking weight X le 

verage. 

Friction. 

Effective strain. 

1 

.755 

.242 

.182710 









2 

.754 

.241 

.181714 


1833. 







3 

.753 

.242 

. 182226 

1 

May 30, 

.182226 

72° 

275 

8250 

412 

7838 

4 

.752 

.242 

.181984 









5 

.752 

.242 

.181984 









6 

.752 

.242 

.181984 

2 

tt 

.183407 

68 

357 

10710 

535 

10175 

7 

.752 

.242 

.181984 









8 

.752 

.242 

.181984 









9 

.752 

.242 

,181984 

3 

it 

.182602 

68 

368 

11040 

552 

10488 

10 

.752 

.242 

.181984 









11 

.753 

.241 

.181473 









12 

.753 

.242 

.182226 

4 

U 

.182736 

68 

368 

11040 

552 

10488 

13 

.753 

.242 

.182226 









14 

.753 

.242 

.182226 









15 

.753 

.242 

.182226 

5 

U 

•182226 

528 

347 

10410 

520 

9890 

16 

.753 

.242 

.182226 









17 

.753 

.241 

.181473 









18 

.753 

.242 

.182226 

6 

a 

.181849 

69.5 

336 

10080 

504 

9576 

19 

.753 

.242 

.182226 









20 

.753 

.242 

.182226 









21 

.753 

.243 

.182976 

7 

June 1, 

.181984 

73. 

375 

11250 

562 

10688 

22 

.753 

.243 

.182979 









23 

.752 

.243 

.182736 









24 

.752 

.244 

.183488 

8 

tt 

.182226 

73. 

376 

11280 

564 

10716 

25 

.752 

.245 

.184240 









26 

.751 

.244 

.183244 









27 

.752 

.244 

.183488 

9 

tt 

.181749 

73.25 

380 

11400 

570 

10830 

Mean of 27.182387 













10 

tt 

.182710 

73.5 

348 

10440 

522 

9918 


Maximum 

.184240 










Minimum 

.181473 













11 

tt 

.181984 

73.5 

357 

10710 

535 

10175 

Mn. of the 2 .182856 









Diff. of the 2 .002767 


Mean of 11 

.182236 

n 





























167 


TABLE LXVIII. 


' and reduced by filing. Gauged at points from 1 to 27 inches. Sped 
Jic gravity 7.7708. 


u 

q> 

p, 



cn 

rj 

P 

o 

• 

3 

■*-> 

o 



cl 

C 

REMARKS. 


o 


c v 

4j U 

a 


u a 

p 

to 

Crt 

© 

P* 


43012 

No. 19 

The whole bar in the machine. 

55477 

« 26# 

Part now in from 19 to 27. 

57436 

“ 204 


57394 

“ 23 


54273 

“ 14| 

Part now in the machine from 4 to 19—in tin from 94 to 13. 

52657 

“ 164 


58730 

“ 9i 


58807 

“ 144 

Broke within the wedges. 

59593 

“ 114 

Broke at a part which had been heated. 

54283 

“ l 

Piece now in has not been tried before. 

55911 

“ 4 

The mean area of the 11 sections of fracture is .000151 square 
inch less than that of the 27 measured sections. 
















168 


TABLE LXIX. 

Experiments on bar No. 223 E. From Missouri. Manufactured 
by Mr. Massey , at the Maram.ee Iron Works. Drawn under the ham - 3 





Areas of section at 
the points measured be¬ 
fore trial. 

w 

S 


0 

8-s 


s 

t ^ 

X 



00 

JX 

~ 

§ 

Breadth. 

Thickness. 

•c 

£* 

X 

0> 

X 

w 

O 

6 

fc 

DATE. 

• 

Area of the sectit 

fracture before tris 

Temperature, F; 

Breaking weigh 

the scale. 

Breaking weigh 

leverage. 

Friction. 

Effective strain. 

1 

.742 

.242 

.179564 









2 

.741 

.240 

.177840 









O 

O 

.742 

.236 

.175112 


1833. 


C550° 7 
l 71 5 





4 

5 

.740 

.742 

.238 

.237 

.176120 

.175854 

1 

June 6, 

.178055 

280 

8400 

420 

7980 

6 

.740 

.240 

.177600 









7 

.740 

.240 

.177600 









8 

.740 

.241 

.178340 

2 

U 

.176001 

71 

298 

8940 

447 

8493 

9 

.741 

.241 

.178581 









10 

.741 

.241 

.178581 

3 

U 

.176365 

71 

301 

9030 

451 

8579 

11 

.740 

.239 

.176860 









12 

.741 

.240 

.177840 

4 

a 

.177186 

71 

301 

9030 

451 

8579 

13 

.741 

.239 

.177099 









14 

.741 

.239 

.177099 

5 

a 

.177915 

71 

310 

9300 

465 

8835 

15 

.741 

.239 

.177099 









16 

.741 

.239 

.177099 

6 

a 

.177170 

71 

310 

9300 

465 

8835 

17 

.740 

.238 

.176120 









18 

.740 

.240 

.177600 

7 

u 

.178270 

71 

305 

9150 

457 

8693 

19 

.740 

.240 

.177600 









20 

.740 

.239 

.176860 

8 

June 13, 

.177099 

71 

312 

9360 

468 

8892 

21 

.740 

.238 

.176120 









22 

.740 

.239 

.176860 

9 

U 

.178007 

71 

312 

9360 

468 

8892 

23 

.740 

.240 

.177600 









24 

.741 

.238 

.176358 

10 

« 

.178370 

71 

320 

9600 

480 

9120 

25 

.741 

.238 

.176358 









26 

.738 

.238 

.175644 

11 

u 

.177600 

71 

320 

9600 

480 

9120 

27 

.738 

.239 

.176382 









27.3 

.745 

.239 

.178055 

12 

u 

.175616 

71 

320 

9600 

480 

9120 

Mean of 28 

.177137 

Mean of 12 .177304 







Maximum .179564 
Minimum .175112 


Mean of these 2 .177338 
Diff. of the 2 .004452 






































169 


TABLE LXIX. 

mer, reduced by filing , and gauged at points one inch apart. Specific 
gravity , 7.6742. ^ J 


Strength in lbs. per 
square inch. 

Point of fracture. 

REMARKS. 



f - ^ ut ' nto tin from 22 to 25*. After a strain of 273 lbs. the 

44818 

No. 27^- 

J packing gave way. The temperature of the tin at this time 



1 being 550°. After this the bar was broken up at 71°. Broke 



Lnear the wedges—had not been in tin. 

48255 

" 25^ 

Had barely touched the tin. 

48592 

“ 16| 


48418 

“ 23J 

Shorter piece now in from 16f to 25*. 

49799 

“ 19* 


49811 

“ 22* 


48763 

“ 1| 

Longer piece now under trial from 1 to 16*. 

50209 

“ m 


49953 

“ 10* 


51129 

“ 8| 


51351 

“ 


51931 

“ 3* 




The mean area of the 12 sections of fracture was .000167 square 



inch greater than that of the 28 measured sections. 


/ 

















170 


TABLE LXX. 

Experiments on bar No. 224 A. Manufactured by Messrs. > 
Yeatman fy Woods of Nashville, Tennessee. Drawn under the ham- y 


C/5 

■A 

s 

Breadth. 

Thickness. 

Area before trial. 

]N o. of the experiment. 

DATE. 

Area of the sections 

of fracture. 

Temperature, Fah. 

Breaking weight in 

the scale. 

Breaking weight X 

leverage. 

Friction. 

Effective strain. 

1 

.753 

.233 

.175449 


1833. 







2 

.754 

.233 

.175682 

1 

May 23. 

.176202 

82 

311 

9330 

466 

8864 

3 

.755 

.233 

.175915 









4 

.753 

.233 

.175449 









5 

.754 

.234 

.176436 

2 

it 

.175536 

82 

327 

9810 

490 

9320 

6 

.754 

.232 

.174928 









7 

.753 

.233 

.175449 









8 

.753 

.234 

.176202 

3 

a 

.175799 

82 

327 

9810 

490 

9320 

9 

.753 

.233 

.175449 









10 

.752 

.234 

.175968 









11 

.753 

.234 

.176202 

4 

it 

.174928 

82 

327 

9810 

490 

9320 

12 

.748 

.233 

.174284 









13 

.753 

.232 

.174696 









14 

.754 

.230 

.173420 

5 

u 

.174703 

82 

322 

9660 

483 

9177 

15 

.754 

.232 

.174928 









16 

.753 

.233 

.175449 









17 

.753 

.232 

.174696 

6 

it 

.175245 

578 

364 

10920 

546 

10374 

18 

.755 

.233 

.175915 









19 

.753 

.233 

.175449 









20 

.752 

.233 

.175216 

7 

May 25. 

.175216 

76 

379 

11370 

568 

10802 

21 

.754 

.234 

.176436 









22 

.754 

.235 

.177190 









23 

.753 

.234 

.176202 

8 

tt 

.176907 

76 

386 

11580 

579 

11001 

24 

.753 

.234 

.176202 









25 

.755 

.235 

.177425 









26 

.752 

.233 

.175216 

9 

>( 

.176202 

76 

400 

12000 

600 

11400 

27 

.755 

.231 

.174405 









Mean of 27 .175422 

10 

tt 

.175565 

76 

386 

11580 

579 

11001 


Maximum . 177425 










Minimum . 173420 

11 

it 

.175188 

76 

394 

11820 

591 

11229 

Mean of the 2.175422 


Mean of It 

.175772 






DifF. of the 2 .004005 





\ 



































171 


TABLE LXX. 


mer , subsequently reduced by filing, and gauged at every inch. Specific 
gravity 7.8319. 


Strength in pounds 
per square inch. 

Point of fracture. 

REMARKS. 

50306 

00 

• 

o 

& 


53095 

“ If 


53020 

“ 3| 


53279 

“ 6 


52511 

“ Ilf 


59197 

“ 19f 

Broke in tin,—Part included in the machine from 17i to 22. 

61649 

“ 26 


62185 

“ 21f 


64699 

“ 24 


62660 

00 

l-H 


64668 

“ 15^ 

The mean area of the 11 sections of fracture is .000350 square 
inch greater than that of the 27 measured sections. 




15 











172 


TABLE LXXI. 

Experiments on bar No. 224 B. Manufactured by Messrs. £ 
Yeatman fy Woods , at Nashville , Tennessee. Drawn with the hammer , $ 


Marks. 

Breadth. 

Thickness. 

Area before trial. 

No. of the experiment. 

DATE. 

Area of the section at 

the point of fracture. 

Temperature, Fah. 

Breaking; weight in 

the scale. 

Breaking weight \ 

levei'age. 

Friction. 

Effective strain. 

Strength in pounds 

per square inch. 

0 

.765 

.236 

.180540 


1833. 








1 

.759 

.237 

.179883 

1 

June 27. 

.178947 

574° 

322 

9660 

483 

9177 

51283 

2 

.759 

.236 

.179124 










3 

.759 

.241 

.182919 

2 


.179693 

564 

329 

9870 

493 

9377 

52183 

4 

.758 

.236 

.178888 










5 

.758 

.237 

.179646 

3 

<i 

.179646 

578 

350 

10500 

525 

9975 

55526 

6 

.758 

.237 

.179646 










7 

.760 

.236 

.179360 

4 

it 

.179646 

578 

356 

10680 

534 

10146 

56478 

8 

.760 

.236 

.179360 










9 

.758 

.236 

.178888 

5 

tt 

.179431 

520 

368 

11040 

552 

10488 

58451 

10 

.758 

.237 

.179646 










11 

.758 

.236 

.178888 

6 

tt 

.179646 

100 

390 

11700 

585 

11115 

61872 

12 

.758 

.237 

.179646 




app. 






13 

.758 

.237 

,179646 

7 

tt 

.180376 

100 

390 

11700 

585 

11115 

61621 

14 

.758 

.237 

.179646 




app. 






15 

.759 

.237 

.179883 

8 

tt 

.179267 

75 

398 

11940 

597 

11343 

63275 

16 

.759 

.236 

.179124 










17 

.754 

.237 

.178698 

9 

it 

.179503 

75 

405 

12150 

607 

11543 

64305 

18 

.758 

.236 

.178888 










19 

.756 

.236 

.178416 










20 

.758 

.237 

.179646 

10 

tt 

.179457 

75 

390 

11700 

585 

11115 

61937 

21 

.753 

.237 

.178461 










22 

.755 

.238 

.179690 










23 

.757 

.238 

.180166 




1100 






24 

.758 

.237 

.179646 

11 

June 29. 

.179492 

to 

168 

5040 

252 

4788 

26675 

25 

.758 

.236 

.178888 




1200 






26 

.759 

.236 

.179124 










Mean of 27 

.179494 














12 

tt 

.179314 

75 

355 

10650 

532 

10118 

56425 

Maximum= 

.182919 










Minimum= 

.178888 

13 

it 

.179053 

75 

348 

10440 

522 

9918 

55391 

Mean of the 2 .180903 

14 

tt 

.179457 

75 

359 

10770 

538 

10232 

57016 

Diff. of the 2.004031 















Mn. of 14= 

.179494 








o 

3 


V 

a 


Cm 

a 


<L> 

b 

« 


.500 


































173 


TABLE LXX1. 


S reduced by filing to a nearly uniform size , and gauged at every inch. 
I Specific gravity 7.8046. ’ 


1 . 

Area after fracture. 

Area after , in parts of 

that before fracture. 

Point of fracture. 



No. 254 



a 

154 



u 

13f 



it 

12 



u 

6* 



(t 

n 




0i 



tt 

4* 



a 

H 



a 

9 *1 

.065000 

.362 

u 

19J s 



u 

15J h 



a 

m 



u 

244 

ti 


.130 


REMARKS. 


Part in tin from 4 to 8. 

Do. 

Do. 

Do. 

Broke in tin.—Temperature had been at 590°. 


This is a different piece from the preceding—part 
on the opposite side of the hot fracture. 

f Put on 336 lbs. which it bore without signs of 
| yielding—took off one half the weight and thenap 


Broke at a part most remote from the portion just 


The mean area of the 14 sections of fracture is iden- 

























174 


TABLE LXXII. 

Experiments on bar No. 224 C. Manufactured by Messrs. Teat- ? 
man fy Woods , at Nashville , Tennessee. Brawn under the hammer , \ 


Marks. 

Breadth. 

Thickness. 

Area of section at the 
points measured. 

. 

Number of the ex¬ 
periment. 

DATE. 

Area of the section at 

the point of fracture. 

Temperature, Fah. 

Breaking weight in 

the scale. 

Breaking weight X 

leverage. 

Friction. 






1833. 






0 

.760 

.238 

.180880 

1 

June 29. 

.183828 

580° 

311 

9330 

466 

1 

.757 

.242 

.183194 



< 





2 

.756 

.241 

.182196 








3 

.756 

.239 

.180684 

2 

€i 

.182400 

590 

311 

9330 

466 

4 

.756 

.241 

.182196 








5 

.757 

.242 

.183194 








6 

.757 

.241 

.182437 

O 

O 

<< 

.184265 

562 

378 

11340 

567 

7 

.757 

.242 

.183194 








8 

.757 

.242 

.183194 








9 

.760 

.241 

.183160 

4 

<* 

.183171 

80 

401 

12030 

601 

10 

.759 

.242 

.183678 








11 

.761 

.243 

.184923 








12 

.759 

.243 

.184437 

5 

a 

.182945 

80 

401 

12030 

601 

13 

.760 

.242 

.183920 








14 

.760 

.239 

.181640 








15 

.760 

.241 

.183160 

6 

July 6, 

.183748 

80 

351 

10530 

526 

16 

.761 

.242 

.184162 








17 

.761 

.242 

.184162 








18 

.761 

.243 

.184923 

7 

a 

.183160 

80 

369 

11070 

553 

19 

.760 

.241 

.183160 








20 

.760 

.241 

.183160 








21 

.760 

.240 

.182400 

8 

<( 

.182626 

77 

231 

6930 

346 

22 

.761 

.241 

.183401 








23 

.759 

.242 

.183678 








24 

.761 

.241 

.183401 

9 


.183470 

77 

249 

7470 

373 

25 

.760 

.240 

.182400 








26 

.763 

.241 

.183883 

10 

a 

.183141 

77 

253 

7590 

379 


Me 

an of 27 

r .183141 

11 

<c 

.182650 

77 

256 

7680 

384 


Maximum .184923 

12 

a 

.182445 

77 

237 

7110 

355 


Minimum 

.180684 












13 

€C 

.182529 

77 

249 

7470 

373 


Mean of these 2 .182803 


* 







Diff. of the 2 .004341 

14 

it 

.181169 

77 

255 

7650 

382 


Mean of 14 .183110 












































175 


TABLE LXXII. 

reduced by filing to a nearly uniform size , and gauged at every inch. 
Specific gravity , 7.7781. 



u 



a. 


2 

•» 

cn 

e 

• 

rs 

<v 

u 

a 

> 

♦-> 

V 

SB 

w 

Strength i 
square inch. 

CJ 

£ 

4-» 

g 

’3 

P< 

8864 

48219 

No. 1 5$ 

8864 

48596 

“ 14$ 

10773 

58465 

“ 12* 

11429 

62395 

“ 8 * 

11429 

62472 

“ 4f 

10004 

54226 

“ 18$ 

10517 

57420 

“ 20 

6584 

36052 

“ 5$ 

7097 

38682 

“ 23f 

7211 

39374 

“ 25* 

7296 

39945 

« 21 * 

6755 

37025 

“ 4* 

7097 

38887 

“ H 

7268 

40118 

. i 

“ o* 


REMARKS. 


Part in tin from 3 to 6*. 


r 
1 


Being less than 6 inches from the tin, the place 
of this fracture was probably heated to 150 or 200° 
at the time. Calculating for this weight (378 lbs.) 
on the smallest section now in the tin, it gives 
59623 lbs. per square inch. 


After this fracture the section was found to be 
in breadth, .572; thickness, . 159; area .090948; 
showing the present area to be less than half the 
original section, for .090948x2=. 181896. 

The piece now under trial had been previously 
tried with only 311 lbs. in the scale, having been 
broken off at the first experiment. 


r 


The same piece as in the preceding trial. 

Short piece .—Had been in tin .—Area at the time 
of this trial .150664. Calculating on this area, we 
obtain a strength of 43700 lbs. per square inch. 
This and the following experiments were on an¬ 
nealed sections. 

Had not been in tin. 


Do. 


Do. 


Had been in tin. 


The mean area of the 14 sections of fracture is 
.000031 square inch less than that of the 27 measured 
sections. _ 


15 * 


















176 


TABLE LXXIII. 


Experiments on bar No. 224 D. Manufactured by Messrs. ) 
Yeatman Woods, at Nashville , Tennessee. Brawn by the hammer , ) 


Marks. 

y 

Breadth. 

Thickness. 

1 

Area of section before 
trial. 

No. of the experiment. 

DATE. 

Area of the section of 

fracture before trial. 

Temp. Tab. 

Breaking; weight in 

the scale. 

Breaking weight X 

leverage. 

Friction. 

Effective strain. 

Strength in pounds 

per square inch. 

Breadth after fracture. [ 

0 

.768 

.237 

.182016 











1 

•755 

.237 

.178935 


1833. 

< 

o 







2 

.756 

.239 

.180684 

1 

July 13, 

.184558 

570 

314 

9420 

471 

8949 

48489 

.518 

3 

.757 

.239 

.180923 











4 

.759 

.241 

.182919 











5 

.760 

.243 

.184680 











6 

.760 

.240 

.182400 

2 

u 

.186010 

550 

314 

9420 

471 

8949 

48110 


7 

.760 

.242 

.183920 











8 

.759 

.242 

.183678 

3 

u 

.183920 

560 

322 

9660 

483 

9177 

49891 


9 

.758 

.242 

.183436 











10 

.758 

.242 

.183436 

4 

u 

.184110 

540 

340 

10200 

510 

9690 

52631 


11 

.758 

.242 

.183436 











12 

.760 

.242 

.183920 











13 

.760 

.243 

.184680 











14 

.760 

.242 

.183920 

5 

u 

.178935 

440 

372 

11160 

558 

10602 

59262 


15 

.760 

.242 

.183920 




• 







16 

.760 

.245 

.186200 











17 

.760 

.245 

.186200 

6 

ii 

.183436 

80 

375 

11250 

562 

10688 

58265 


18 

.760 

.244 

.185440 

7 

a 

.183678 

80 

375 

11250 

562 

10688 

58189 


19 

.760 

.244 

.185440 











20 

.760 

.243 

.184680 

8 

a 

.183540 

80 

378 

11340 

567 

10773 

58696 


21 

.759 

.243 

.184437 











22 

.759 

.240 

.182160 











23 

.759 

.241 

.182919 

9 

a 

.182970 

80 

378 

11340 

567 

10773 

58878 


24 

.759 

.241 

.182919 











25 

.760 

.241 

.183160 











26 

.763 

.239 

.182357 















10 

July 18, 

.180863 

76 

221 

6630 

331 

6299 

34827 


Mean of 27= 

=.183439 















11 

ii 

.180475 

76 

234 

7020 

351 

6669 

36952 

.456 

Maximum= 

.186200 

12 

a 

.182892 

76 

234 

7020 

351 

6669 

36464 


Minimum= 

.178935 

13 

ii 

J 

.182350 

76 

236 

7080 

354 

6726 

36885 






14 

a 

.182919 

76 

236 

7080 

354 

6726 

36770 


M 

n. of the 2 

.182567 











Diff. of the 2 . 00725 


Mn. of 14 = 

J .182912 















































177 


TABLE LXXIII. 


reduced by filing to a nearly uniform size, marked and gauged at every 
inch . Specific gravity 7.8046. 


o 

C5 


u 

© 


a 

u 

© 


.150 


,130 


u 

3 

♦-» 

© 

C3 

C 

© 

.*5 

© 

u 

< 


.077700 


.059280 


Cm 

O 

p © 
3 3 
© 

’ 

s- ~ 

1) © 
*■* 

cs c2 

S.S 

^ 4-> 

«< GJ 

■c 


.421 


.328 


© 

U 

3 

+-> 

© 

c3 


© 


O 

Ph 


No 20£ 

“ 17* 
“ 14 


u 


121 


n 


a 


a 


u 


u 


9i 

8 

6 | 


5f 


21 


0 i 


tt 

“ 251 
“ 221 
“ 231 


REMARKS. 


f Part in tin from 1 ^ to 51. Before the fracture the 
J part from No. 7 to 20 was found to be 15 3-10 inches 
1 long, ana had consequently stretched 2 3-10 inches 
Lor a little more than 1-6 of its original length. 

C Broke at the remotest part from the tin which is 
C. still in the same place as above. 

C Fracture very near the wedges. This experiment 
< would by calculating on the smallest section in tin 
C. give a strength of 54058 lbs. per square inch, 
f Reduced in area at No 1. But not actually broken, 
j It had borne 360 lbs. while at a temperature of 
570°. The smallest section in tin, which is the 
smallest in the bar, is the one on which the caleu- 
Llation is made in the table. 

Broke soon after applying the weight. 

Yielded very gradually. 


1 


f The part remaining after this experiment from 0 to 
J No. 5 had become 5.93 in. in length. Extension 

! =5 3^5 of the original length. 

C From this experiment to the end of the series, the 
\ trials were on annealed sections. 


Th^ mjeau area of the 14 sections of fracture is 
000527 square inch less than that of the 27 measured 
sections. 
















a > a l ^ooisD^o^ooo*<»cr>tn^ootoi-io<ooo^[0>Ot»{i.oo^OH-‘0 Marks, 


178 


TABLE LXXIV. 

Experiments on bar No. 224 E. Manufactured by Messrs. Yeat- 7 
man ^ Woods , at Nashville , Tennessee. Brawn by the hammer, 5 


Breadth. 

Thickness. 

\ 

Area before trial. 

No. of the experim’nt. 

BATE. 

Area of the section of 

fracture before trial. 

Temperature, Fah. 

Breaking weight in 

the scale. 

Breaking weight X 

leverage. 

Friction. 

.753 

.243 

.182979 


1833. 






.753 

.239 

.179967 

1 

July 11, 

.178224 

566° 

305 

9150 

457 

.753 

.238 

.179214 








.752 

.238 

.178976 

2 

(( 

.178105 

570 

319 

9570 

478 

.752 

.237 

.178224 








.752 

.238 

.178976 

3 

ii 

.178976 

554 

329 

9870 

493 

.750 

.237 

.177750 








.753 

.237 

.178461 

4 

<< 

.177562 

573 

334 

10020 

501 

.753 

.236 

.177708 








.749 

.237 

.177513 

5 

< C 

.178976 

560 

351 

10530 

526 

.752 

.237 

.178224 








.752 

.237 

.178224 

6 

<< 

.178047 

560 

351 

10530 

526 

.753 

.237 

.178461 








.752 

.237 

.178224 

7 

a 

.178698 

560 

367 

11010 

550 

.754 

.236 

.177944 








.754 

.237 

.178698 

8 

€C 

.179468 

82 

322 

9660 

483 

.754 

.237 

.178698 








.754 

.237 

.178698 

9 

July 12, 

.178976 

82 

375 

11250 

562 

.754 

.237 

.178698 








.750 

.236 

.177000 

10 

C( 

.180480 

82 

385 

11550 

577 

.751 

.236 

.177236 








.752 

.240 

.180480 

11 

ii 

.177059 

82 

394 

11820 

591 

.752 

.240 

.180480 








.752 

.240 

.180480 

12 

ii 

.180480 

82 

394 

11820 

591 

.751 

.240 

.180240 








.752 

.238 

.178976 

13 

ii 

.173342 

82 

383 

11490 

574 

.752 

.238 

.178976 











14 

it 

.178342 

82 

383 

11490 

574 

Mean of 27 .178870 











15 

it 

.178321 

82 

397 

11910 

595 

Maximum 

.182979 








Minimum 

.177000 

Mean of 15= 

=.178337 






Mn. of these 2 .179989 
DiflT. of the 2 .005979 I 





































179 


TABLE LXX1V. 

reduced by filing to a nearly uniform size , marked and gauged at every 
inch from 0 to 26, inclusive. Specific gravity , 7.8046. 



<V 

A 




3 

£ 

r3 

V 



u 

4-> 

to 

0) 

.3 

w 

o 

rt 


REMARKS. 

> 

v» 

tJc2 

es 

£ 



sc 


© 



w 

CD 3 

a* 

to 

Ph 



8693 

48776 

No. 

4 

C Part in tin from 16 to 20 . This was therefore a 
£ cold fracture. 

9092 

51048 

U 

6 i 

Cold fracture. 

9377 

52392 

u 

26^ 

Cold fracture. 

9519 

53576 

u 

8 f 

^ Warm at the section of fracture. On the oppo- 
^ site part of the bar to the preceding. 

10004 

55896 

a 

2 5| 

Broke near the wedges. 

10004 

56287 

u 

9$ 

C Broke near the wedges, on the side of tin bath 
opposite to that of the preceding fracture. 

10460 

58534 

u 

18 

Broke in tin. 

9177 

51134 

u 


c This piece had been broken off in the first ex- 
£ periment on the bar. 

10688 

59662 

u 

25 


10973 

60799 

u 

22 i 


11229 

63419 

u 

19i 


11229 

62273 

u 

21 i 


10916 

61208 

u 

Hi 

Different piece from the preceding. 

10916 

61208 

•< 

12 i 


11315 

63453 

u 

14* 



The mean area of the 15 sections of fracture is 
.000533 less than that of the 27 measured sections. 




















180 

TABLE LXXV. 

Experiments on bar No. 231, Russian iron. Obtained from Messrs. 
Jackson fy Riddle , iron merchants of Philadelphia. Reduced by ham - 


Marks. 

Breadth. 

Thickness. 

i 

Area before trial. 

1 

.800 

.239 

.191200 

2 

.800 

.238 

.190400 

3 

.800 

.238 

.190400 

4 

.799 

.244 

.194956 

5 

.799 

.242 

.193358 

9 

.798 

.240 

.191520 

7 

.800 

.237 

.189600 

8 

.800 

.241 

.192800 

9 

.797 

.240 

.191280 

10 

.800 

.235 

.188000 

11 

.800 

.238 

.190400 

12 

.800 

.239 

.191200 

13 

.800 

.240 

.192000 

14 

.798 

.237 

.189126 

15 

.798 

.236 

.188328 

16 

.800 

.236 

.188800 

17 

.800 

.237 

.189600 

18 

.800 

.237 

.189600 

19 

.801 

.237 

.189837 

20 

.801 

.237 

.189837 

21 

.800 

.239 

.191200 

22 

.798 

.237 

.189126 


Mean of 22 .190980 


Maximum .194956 
Minimum .188000 


Mn. of the 2 .191478 


DifF. of the 2 .006956 


No. of the exp’t. 

DATE. 

Area of the section of 

fracture before trial. 

1 

1834. 
Aug. 9, 

u 

.193437 

2 

a 

.191600 

3 

a 

.192800 

4 

« 

.193891 

5 

u 

.198800 

6 

u 

.189837 

7 

a 

.189126 

8 

u 

.188328 

9 

« 

.189629 


Mean of 9 .191938 


Temperature, Fah. 

Breaking weight in 

the scale. 

Breaking weight X 

leverage. 

o . 
e* 
i-. 

465 

13950 

72.5 

518 

15540 

72.5 

518 

15540 

72.5 

540 

16200 

73. 

525 

15750 

574. 

514 

15420 

75. 

588 

17640 

75. 

609 

18270 

75. 

643 

19290 


F riction. 

Effective strain. 

Strength in lbs. per 

square inch. 

697 

13253 

68513 

777 

14763 

77051 

777 

14763 

76571 

810 

15390 

79374 

787 

14963 

78835 

771 

14649 

77166 

882 

16758 

88607 

913 

17357 

92163 

964 

18326 

96641 













































181 


TABLE LXXV. 

mering and filing in the usual way. Specific gravity , 7.8014. 


Specific gravity of the 
parts in the vicinity of 
the section of fracture. 

Point fractured. 

REMARKS. 

7.7945 

No. 34 

The first permanent elongation perceived, was taken under a 
weight of 308 lbs. 

C This fracture developed a seam or flaw in the direction 

7.7985 

« 12* 

£ of the length. 

Fracture smooth and fine, but not entirely uniform. 

7.8231 

“ 8 

C Took off 14 lbs. of the weight used in last experiment, 

£and restored them gradually. 

7.8702 

" 4# 

Broke in the gripe of the wedges. 

7.7586 

“ lOf 


7.8307 

"19* 


7.8211 

“ 14 

This fracture presented a steely or crystalline appearance. 

7.7650 

“ 15 

Do. (in part.) 

7.7831 

“ 18* 

Do. 

End piece. 

7.7696 

Mn 7.8014 


The mean area of the 9 sections of fracture was greater than 
that of the 22 measured sections, by .000958 square inch, which 
is one half of one per cent, of their mean magnitude. 

















182 


TABLE LXXVI. 

Experiments on bar No. 232, Swedish iron. Obtained from Messrs. 
Jackson 8f Riddle,—taken at random from a latge number—slit with 
the chisel lengthwise , and then reduced by hammering and filing to a 


Marks. 

Breadth. 

Thickness. 

Area before trial. 

No. of the experiment. 

DATE. 

Area of the section of 
fracture before trial. 

r 

XI 

a 

& 

3 

•*-> 

a 

u 

<v 

A 

S 

V 

H 

Breaking weight. 

Breaking wlit. X le¬ 

verage. 

.2 

ZJ 

pH 

Effective strain. 

1 

.801 

.234 

.187934 









2 

.801 

.234 

.187934 


1834. 







3 

.801 

.233 

.186633 

1 

Septem. 

.187872 

72 

376 

11280 

564 

10716 

4 

.800 

.233 

.186400 









5 

.800 

.234 

.187200 









6 

.800 

.234 

.187200 

2 

a 

.187798 

72 

393 

11790 

589 

11201 

7 

.800 

.232 

.185600 









8 

.800 

.232 

.185600 









9 

.800 

.233 

.186400 

3 

u 

.186809 

947 

313 

9390 

469 

8921 

10 

.800 

.234 

.187200 









11 

.800 

.233 

.186400 









12 

.800 

.233 

.186400 

4 


.185262 

56 

457 

13710 

685 

13025 

13 

.800 

.232 

.185600 









14 

.802 

.232 

.186064 

5 

a 

.186599 

56 

464 

13920 

696 

13224 

15 

.802 

.233 

.186866 









16 

.802 

.231 

.185262 

6 

(( 

.186400 

56 

464 

13920 

696 

13224 

17 

.802 

.231 

.185262 









18 

.802 

.232 

186064 

7 

a 

.187200 

56 

461 

13830 

691 

13139 

19 

.808 

.233 

.188264 









20 

.807 

.233 

188031 

8 

a 

.186400 

56 

468 

14040 

702 

13338 

21 

.801 

.233 

186633 









22 

.803 

.233 

187099 

9 

u 

.187434 

55 

474 

14220 

711 

13509 

23 

.803 

.233 

187099 









24 

.803 

.233 

187099 

10 

it 

.186600 

55 

479 

14370 

718 

13652 

25 

.806 

.233 

187798 









26 

.807 

.235 

189645 

11 

44 

.188089 

55 

406 

12180 

609 

11571 

27 

.807 

.233 

188031 









28 

.803 

.234 

187872 

12 

a 

.187565 

55 

434 

13020 

651 

12469 

29 

.802 

.234 

187668 









30 

.803 

.234 

187872 

13 

a 

,.187099 

55 

462 

13860 

693 

13167 

31 

.805 

.232 

186760 














Mn. of 13 = 

.187009 







Mean of 31 .186935 


Maximum .188264 
Minimum . 185600 


Mn. of the 2.186932 
3iff. of the 2 .002664 












































1S3 


TABLE LXXVI. 


{ 


suitable size for the experiments. Specific gravities of the different 
sections as in the last column , mean of 6 trials, 7.4587. 


Strength in lbs. per 
square inch. 

Point of fracture. 

REMARKS. 

57039 

No. 28 

First perceptible elongation taken with 196 lbs. in the scale. 
Specific gravity of the end part, 7.6106. 

59644 

52401 

“ 25 

“ 18* 

With 380 lbs., 24 inches in length had become 25 nearly. 

Used the pyrometer with a new screw and revolving weight. 
Each degree weighs 4-7 of a grain of steam. Specific gravi¬ 
ty 7-5118. 

70030 

“ 16 


70868 

“ 14# 

Specific gravity 7.4414. 

70965 

“ 11 


70186 

“ 5i 


71555 

“ 9 


72073 

“ 1 # 


73161 

“ 4i 

Specific gravity 7.5052. 

61518 

“ 19# 

Specific gravity 7.367. 

66478 

“ 20 j 

Specific gravity 7.3133. 

70376 

“ 22# 

The mean area of the 13 sections of fracture is .000074 square 
inch greater than that of the 31 sections measured before trial. 


16 













184 


TABLE LXXVII. 

Experiments on bar No. 233. Swedish iron. Reduced to uniform > 
size as in the preceding table. Specific gravity , by a mean of 7 trials on $ 


No. of the mark. 

Breadth. 

Thickness. 

Area of sections mea¬ 

sured before trial. 

No. of the experim’t. 

DATE. 

Area of the section 

of fracture before trial. 

Temperature, Fah. 

| Weight in the scale. 

Weight X leverage. 

Friction. 

1 

.802 

.226 

.181252 


1836. 

V 





2 

.800 

.227 

.181600 

1 

April 16, 

.181178 

65° 

371 

11130 

556 

3 

.800 

.226 

.180800 








4 

.806 

.226 

.181478 








5 

.803 

.225 

.180675 

2 

it 

.179424 

65 

363 

10890 

544 

6 

.804 

.227 

.182508 








7 

.803 

.227 

.182481 








8 

.802 

.227 

.182054 

3 

it 

.181252 

650-f 

336 

10080 

504 

9 

.802 

.227 

.182054 








10 

.802 

.227 

.182054 








11 

.801 

.226 

.181026 

4 

it 

.181653 

50 

403 

12090 

604 

12 

.802 

.224 

.179648 








13 

.802 

.226 

.181252 








14 

.801 

.225 

.180225 

5 

a 

.180348 

50 

403 

12090 

604 

15 

.801 

.225 

.180225 








16 

.801 

.225 

.180225 


1837. 






17 

.801 

.225 

.180225 

6 

Jan. 5, 

.180225 

530 

378 

11340 

567 

18 

.801 

.225 

.180225 








19 

.801 

.225 

.180225 








20 

.802 

.225 

.180450 

7 

it 

.180225 

40 

426 

12780 

639 

21 

.802 

.225 

.180450 








22 

.802 

.224 

.179648 








23 

.802 

.226 

.181252 

8 

it 

.180450 

40 

413 

12390 

619 

24 

.802 

.227 

.182054 








25 

.802 

.226 

.181252 








26 

.801 

.227 

.181827 

9 

ti 

.180225 

40 

420 

12600 

630 

27 

.798 

.226 

.180348 








28 

.799 

.227 

.182373 








29 

.800 

.226 

.180800 

10 

t i 

.181252 

40 

408 

12240 

612 

30 

.801 

.224 

.179424 








31 

.800 

.226 

.180800 












•11 

** , 

.181026 

40 

399 

11970 

598 


Mean of 31 .181187 









Maximum .182508 

12 

a 

.182394 

40 

408 

12240 

612 


Minimum .179424 









Mean of the 2 .180966 

13 


.182054 

40 

413 

12390 

619 


Diff. 

of the 2 .003084 












Mean of 13 .180900 

1 


1 
















































185 


TABLE LXXVII. 
different parts of the bar , 7.4983. 


.s 

*3 

w 

cn 

> 

O 

rength in lbs. per 
re inch. 

<3 

u 

S3 

■*-> 

o 

03 

Cm 

Cm 

O 

g 


REMARKS. 

te 

W 

(A 3 
a* 

(fi 

o 

PH 



10574 

58362 

No. 


C Short piece only embraced between the heads of 
£ the machine. 

10346 

57662 

it 

30 

Shorter portion than before. 

9576 

52838 

a 

23 

In hot metal above 650°. 

11486 

63230 

<< 

244 


11486 

63688 

u 

27 


10773 

59775 

Not bro. 

0 Tried in tin from 16 to 19. Not broken. Elonga- 
£ tion on the part in tin, after trial, .25 inch. 

12141 

67365 

it 

174 


11771 

65231 

a 

204 


11970 

66417 

it 

15 


11628 

64153 

a 

04 


11372 

62819 

« 

n 


11628 

63203 

a 

64 


11771 

64656 

u 

84 

The mean area of the 13 sections of fracture is . 00287 
less than that of the 31 sections measured before trial. 





















186 


TABLE LXXVIII. 

Experiments on bar No. 237, a specimen of bar iron manufactured > 
by H. A. Grubb and heirs , Lancaster County, Pennsylvania. Ore taken v 


Marks. 

Breadth. 

Thickness. 

Area of the sections 
measured before trial. 

No. of the experiment. 

BATE. 

A rea at the section ot 

fracture before trial. 

Temperature, Fah. 

Breaking weight in 

the scale. 

Breaking weight X 

leverage. 

Friction. 

Effective strain. 

Strength in pounds per 

square inch. 

Breadth of section after 

fracture. 

— 

1 

.795 

.250 

.198750 



V 








2 

.793 

.250 

.198250 











3 

.796 

.250 

.199000 


1835. 


o 







4 

.797 

.250 

.199250 

1 

July 18, 

.195624 

564 

392 

11760 

588 11172 

57109 

.628 

5 

.796 

.250 

.198500 











6 

.796 

.252 

.200592 











7 

.796 

.252 

.200592 











8 

.794 

.252 

.200088 

2 

July 24, 

.198792 

83 

420 

12600 

630 11970 

60213 

.621 

9 

.791 

.250 

.197750 











10 

.790 

.251 

.198290 











11 

.794 

.251 

.199294 

3 

(« 

.198334 

83 

431 

12930 

646 12284 

61935 

.648 

12 

.794 

.251 

.199294 











13 

.792 

.247 

.195624 











14 

.795 

.251 

.199545 

4 

a 

.199125 

83 

436 

13080 

654 12426 

62403 

.640 

15 

.795 

.250 

.198750 











16 

.791 

.246 

.194586 











17 

.796 

.246 

.195886 

5 

u 

.200592 

83 

448 

13440 

672 12768 

63651 

.640 

18 

.792 

.252 

.199484 











19 

.792 

.252 

.199484 











20 

.794 

.250 

.198500 

6 

u 

.198750 

575 

408 

12240 

612 

11628 

58508 

.668 

21 

.795 

.251 

.199545 











22 

.795 

.249 

.197955 











23 

.796 

.247 

.196614 

7 

u 

.199015 

110 

424 

12720 

636 

12084 

60719 

.663 

Mean of 23= 

:.198502 















8 

u 

.195016 

100 

434 

13020 

651 

12369 

63396 

.619 


Maximum .200592 












Minimum . 194586 















9 

u 

.198110 

100 

452 

13560 

678 

12882 

65024 

.632 

Mean of the 2 .197589 











Diff. of the 2.006006 


Mn. of 9 = 

.198151 






































































187 


TABLE LXXVIII. 


C from the Cornwall ore-hank. Brawn under the hammer , reduced by 
\filing and gauged at every inch. Specific gravity , 7.740. 


Thickness after frac¬ 
ture. 

Area of section after 
fracture. 

Area after comp, with 
that beforetnn\ taken as 
unity. 

Point of fracture. 

REMARKS. 

.178 

.111784 

.571 

No. 13 

r The load first tried in making- this experiment wasi 

1 363 lbs., which the bar bore for some time, but on 
^ changing it for 392 it gave way very soon—result 

.181 

.112401 

.565 

“ 10^ 

| supposed to be a little too high—part in tin from 
L4 to 7 inclusive. 

.192 

.124416 

.627 

00 

*• 


.195 

.124800 

.626 

“ 3 i 


.199 

.129360 

.644 

“ 7 

• 

.200 

.123600 

.621 

“ 24 

r Partin tin from 16| to 21. The temperature of 
< the section of fracture at the moment of breaking 

.186 

.123318 

.619 

“ 14# 

was judged to be not less than 400°. 

.178 

.110182 

.565 

« 15 1 


.199 

.125768 

.634 

« 17# 



1 

.608 


The mean area of the 9 sections of fracture is .000350 
square inch less than that of the 23 measured sections. 


10 * 


























188 


Results of experiments on wrought iron not rolled into plate. 

Among the facts disclosed in this range of results, those respecting 
English cable-bolt iron, are given in tables LXI., LXII. and LXIII. But 
much of the matter in the first two of these tables, refers to the influence 
of high temperatuies. They, however, furnish a mean result, on bar 214, 
for the strength in the cold state, of 57987 pounds to the square inch. On 
bar 212, an experiment, on a deeply filed section, gave 59975, while two 
trials on 213 give a mean of 59351 pounds. Hence the mean of these 
three results, viz: 59105 pounds, represents the strength of the best English 
cable-bolt iron under ordinary circumstances. Table LXIII. presents the 
results on two portions of the above iron, one cut from bar 213, the other 
from 214, and on these portions, the effect of hammer-hardening was tried. 
The bars when drawn out under the hammer, previous to being filed down, 
were hammered until nearly, or quite, cold. It will be seen that the lowest 
result on these two specimens was 65718, the highest 75045, and the 
mean of 8 trials, 71000 pounds. From this statement, it is apparent that 
the process applied augments, very sensibly, the tenacity of the material; 
for the lowest result in this table, is 5743 pounds, or 9.5 per cent., above 
the highest of the three just detailed, as given by the metal in its ordinary 
state ; while the mean of the hammer-hardened specimens, is 11282 pounds 
or 19.2 per cent, above the mean strength of those which had been only 
hammered out in the ordinary way, and left to cool off from a red heat 
without the simultaneous application of any mechanical action. 

Table LXIY. contains the experiments on a specimen of wire, about one- 
third of an inch in diameter. The maximum strength at 50°, is 88354 
pounds per square inch, the minimum 72325, (the latter being on a part 
annealed before trial,) and the mean of all the trials 81387. 

Experiments 3, 4, 5, and 6, on this wire, gave results so nearly identical, 
that we may perhaps more properly assume their mean as its true average 
strength, equal to 84186 pounds per square inch, at from 60 to 66 degrees 
Fahrenheit. From this mean the diminution by annealing, is 14 per cent. 

By the first 5 experiments, in table LXXV., it appears that the strength 
of Russian bar iron, at ordinary temperatures, is 76069 pounds per square 
inch. It will be perceived that the specific gravity of this specimen is 
considerably higher than that of most other samples of metal, which we 
have examined. Its superiority in point of tenacity is, probably, attributable, 
in a great degree, to the refining process to which it had been subjected. 
The fracture was of a peculiarly fine, fibrous appearance, and had generally 
a tolerably regular bevel or chisel edge, across the thickness of the bar. 

In the tables numbered from LXV. to LXIX., will be found an account 
of experiments on 5 bars of iron, manufactured in Missouri; and in those 
numbered from LXX. to LXXIV., are recorded the operations on the same 
number of bars made near Nashville in Tennessee. In the case of these, as 
well as other bars on which some of the trials were marked as at elevated 
temperatures, the fractures often took place at points so remote from the 
source of heat, that the results really belong to “ ordinary temperatures.” 
Including fractures made under the circumstances just alluded to, the number 
of results obtained at those temperatures, on the Missouri iron, is 22, and the 
mean strength 47909 pounds per square inch. On the Tennessee iron, were 
made, under similar circumstances, 21 experiments, giving a mean strength 
ol 52099 pounds. The Missouri bars appeared to possess a coarse fibrous 
structure, and were judged to have undergone but little refining in bringing 
the metal to a malleable state. 


189 


Table LXXVIII. exhibits the tenacity of iron manufactured by Messrs. 
Grubb, of Lancaster county, Pennsylvania, as 58661 pounds per square 
inch. 

While on this subject, we may refer to some following tables of expe¬ 
riments on iron from Salisbury, Connecticut, manufactured from different 
sorts of pig-metal, reserving, however, the particular discussion of those 
tables to a subsequent section of this report. It will be found on inspecting 
table LXXIX. that forty experiments, at comparable temperatures, were 
made on the materials from that quarter, the mean result of which is a 
strength of 58009 pounds per square inch. 

In connexion with the present topic, may also be mentioned the result 
of experiments on specimens of iron manufactured in Centre County, 
Pennsylvania, an account of which will be found in table XCVII. The mean 
strength of three bars, as given by 15 experiments, is 58400 pounds. 
Table CI1. includes, among others, 10 experiments, at ordinary tempera¬ 
tures, on Phillipsburg wire of smaller sizes than that already mentioned. 
Of these, the larger—.19 inch in diameter—will be found to have exhibited, 
at 5 trials, a mean strength of 73880 pounds; and that which had a diameter 
of .156 inch, a strength of 89162 pounds per square inch. 

Collecting together the foregoing details, we have for the strength 


Missouri bar iron, at ordinary temperatures, by 22 exp. 

47909 pounds. 

Siit rods, (Nos. 180 and 182.) 

• 

2 

50000 

Tennessee bar, 

• 

21 

52099 

Salisbury, Conn., 

• 

40 

58009 

Swedish bar, 

• 

4 

58184 

Centre Co., Pa.', 

• 

15 

58400 

Lancaster Co., Pa., 

• 

2 

58661 

English Cable iron, 

• 

5 

59105 

Do. hammer hardened 

• 

8 

71000 

Russian bar, 

• 

5 

76069 


f.333 

13 

84186 

Phillipsburg wire, diam. 

l .190 

5 

73888 


^ .156 

5 

89162 

Cast steel, (Tab. LIX.) 

• 

1 

130681 


Strength of iron made from different sorts of Pig-metal. 

The experiments to determine the effect of different kinds of pig-metal, 
either separate or in mixture, when converted into wrought iron, by the 
same refining process, were performed on bars furnished by the Salisbury 
Iron Company, of Salisbury, Connecticut, of which one specimen, from 
which were formed the two bars 218 A., 218 B., was produced from dead 
gray pig; 219 A., and 219 B., were from a specimen formed from lively 
gray pig ; 220 A. and 220 B., from mottled pig; 221 A. and 221 B. from 
white pig ; and 222 A. and 222 B., from a mixture of all these kinds toge¬ 
ther. By a reference to the tables (from LXXX, to LXXXVIII. inclusive) 
containing details of the trials upon these bars, it will be seen that on 
all of them, some experiments were made at high temperatures, and of 
course that the purpose of the present comparison can be properly accom¬ 
plished, only by referring to those, which were made at, or near the same 
temperature. The experiments at ordinary temperatures embracing the 
mean strength, as well as the irregularities of structure, are preferred as most 
satisfactory in referrence to this point. In presenting these results, care has 


190 


been taken to exclude all those trials in which the effect of heat would be 
appreciable, either during or subsequent to the time of trial. 

It will be seen that if we take into view all the bars of this iron, on which 
experiments were made after they were reduced to a uniform size, and ex¬ 
clude only 219 B., on which the sections were all deeply filed, the advantage 
will appear to be in favour of the metal manufactured from white pig; next 
to which, is that produced from lively gray , giving 98£ per cent, of the 
strength of the first. Next, in the order of strength, will be found the iron 
from dead gray pig , inferior to the first by 1 2-3 per cent.; next, that 
from the mixture of the four kinds of pig which appears to have been 
weaker than the same by 4 4-10 per cent.; and, finally that from mottled 
pig in which the inferiority extended to 5 per cent. The following table 
(LXXIX.) exhibits, at a view, the comparative strength, and the respective 
degrees of uniformity of the several bars, with the strength of some of them 
at high temperatures. 

At elevated temperatures, the results, except that on No. 219 B, are much 
nearer to each other, than those at the points selected for our general com¬ 
parison. On that bar, the trials were upon filed sections. The experiment 
at 573°, giving a strength of66620, exceeded those at corresponding tempera¬ 
tures on the other bars, by an average of about 6222 lbs., or IO 5 per cent.; while 
the two experiments which were made upon it at low temperatures, as will 
be seen by table LXXXII., gave results, the mean of which being 66724 
lbs., surpasses that of the other nine bars by 9275 lbs., or by 16 1-10 per 
cent. Hence we are compelled to believe that this specimen, as it came to 
hand, had undergone the process of hammer-hardening,—a process which 
the direct experiments of the committee have proved to be capable of essen¬ 
tially modifying the tenacity of the metal. 

From the above, it appears, that the greatest difference of strength which 
under ordinary circumstances, can be attributed to differences in the pig- 
metal* from which wrought iron is produced, is about 5 per cent., and that 
under every mode of trial, the article formed from a mixture of different 
kinds of pig, is inferior in tenacity and uniformity to those derived from 
either of the ingredients, unless we except that from mottled gray. And even 
this latter will, on a comparison of all the experiments made upon it, under 
every circumstance, be found superior to the bars from mixed castings. 

If we take into the amount 219 B., the order of values, beginning with the 
highest, will be lively gray , white , dead gray , mixed pigs, mottled ; and 
if we arrange them in the order of their values, as deduced from a compa¬ 
rison of all the experiments , on each kind of iron, with the number of trials 
made on each, we have:—1. lively gray 15 experiments.—2. white 27 
experiments.—3. mottled gray 36 experiments.—4. dead gray 21 experi¬ 
ments.—5. mixed metals 31 experiments. 

So far as these experiments may be considered decisive of the question, 
they favour the lighter complexion of the cast metal, in preference to the 
darker and mottled varieties, and they place the mixture of different sorts, 
among the worst modifications of the materials to be used, where the object 
is mere tenacity. 

* It will be understood that this remark does not apply to pig-iron contaminated 
with sulphur, phosphorus, copper, or other similar impurities ;°but only to such as 
contain different proportions of the ordinary ingredients. 


191 

TABLE LXXIX. 


Comparative table of the effects of using different sorts of pig metal. 


No. of the bar. 

No. of the expt’s. on 
each bar, made at the 
comparable temp. 

Strength exhibited at 

each experiment. 

Mean Strength of each 

bar. 

Difference of maximum 

and minimum of each 

bar. 

Amount of irregularity 

in parts of the mean 

strength. 

Name of the pig, and 

mean strength of the 

two bars of each kind. 

REMARKS. 

218 A. 

1 

2 

10 

11 

58683 

57565 

58459 

61225 

59155 

4360 

.073 

Dead 
gray pig. 

This bar, at 554°, possessed 
a strength of 60457 lbs. per 
square inch. 

218 13. 

1 

2 

3 

4 

5 

53314 

55575 

56339 

58682 

60478 

56877 

7164 

.126 

58016 


219 A. 

1 

2 

3 

4 

8 

52257 

59418 

60204 

57854 

60645 

58075 

8388 

.144 

Lively 

gray. 

This bar at 630° broke 
with 60010 lbs. per. sq. in. 

219 B. 

2 

3 

65640 

67808 

66724 

2168 

.032 

62399 

These two experiments were made 
on very deeply filed sections. At 
573°, this bar gave 66620. 

220 A. 

1 

2 

3 

52503 

52119 

53999 

52873 

1496 

.028 

Mottled. 

At 575° broke with 60988 
lbs. per sq. inch. 

220 B. 

1 

2 

3 

10 

58642 

58108 

58125 

62138 

59252 

4027 

.068 

56062 


221 A. 

1 

8 

9 

53021 

62862 

63081 

59654 

10060 

.168 

White. 

At 520° broke under a 
strain of 60322 lbs. per. sq. 
inch. 

221 B. 

1 

2 

11 

12 

13 

54764 

56054 

57901 

61736 

61140 

58319 

6972 

.119 

58986 


222 A. 

1 

2 

3 

4 

5 

49597 

58924 

60651 

61915 

58895 

57996 

12318 

.212 

Mixed 

pigs. 


222 B. 

1 

2 

3 

4 

51132 

53703 

54407 

59652 

54843 

8500 

.155 

56419 

This bar gave as the mean 
of two experiments at 572° 
60215 lbs. 
































































































192 


TABLE LXXX. 

Experiments on bar 218 A. Manufactured by the Salisbury Iron"] 
Company , at Salisbury, in Connecticut, the ore being obtained from [ 
“Ore Hill” in that town . The kind of pig used, the “dead gray.” { 
Refined after the English method; a loup made and a “gun bar” formed J 

» 


Marks. 

Breadth. 

Thickness. 

Area at the sections 
measured before trial. 

No. of the experiment. 

DATE. 

Area of the section of 

fracture before trial. 

Temperature Fahren¬ 

heit. 

Breaking weight in 

the scale. 

Breaking weight X 

leverage. 

Friction. 

Effective strain. 

0 

.771 

.231 

.178101 


1833. 


o 





1 

.755 

.231 

.174405 

1 

April 20, 

.172895 

556 

356 

10680 

534 

10146 

2 

.755 

.230 

.173650 









3 

.755 

.229 

.172895 

2 

tt 

.176253 

71 

356 

10680 

534 

10146 

4 

.755 

.230 

.173650 









5 

.755 

.230 

.173650 

3 

April 25, 

.172666 

554 

366 

10980 

549 

10431 

6 

.754 

.230 

.173420 









7 

.756 

.230 

.173880 

4 

u 

.173420 

71 

397 

11910 

595 

11315 

8 

.755 

.230 

.173650 









9 

.753 

.230 

.173190 

5 

44 

.173420 

71 

397 

11910 

595 

11315 

10 

.753 

.230 

.173190 









11 

.754 

.229 

.172666 

6 

u 

.173765 

68 

388 

11640 

582 

11058 

12 

.754 

.229 

.172666 


' 







13 

.754 

.229 

.172666 

7 

u 

.173470 

68 

396 

11880 

594 

11286 

14 

.754 

.230 

.173420 









15 

.754 

.230 

.173420 

8 

tt 

.173190 

68 

404 

12120 

606 

11514 

16 

.754 

.230 

.173420 









17 

.754 

.230 

.173420 

9 

(4 

.173497 

68 

392 

11760 

588 

11172 

18 

.755 

.227 

.171385 














Mn. of 9 = 

.173611 







Mean of 19.173512 










Maximum .173101 










Minimum .171385 









Mn. of these 2.174743 









Diff. of the 2.001716 










Experiments on the specimen as received, filing successively two different sections 


Br. Th. 


.486 

.361 

10 

April 22, 

.153576 

50 

315 

9450 

472 

8978 

.502 

.441 

11 

<( 

.221382 

68.5 

481 

14430 

721 

13709 













































193 


TABLE LXXX. 

expressly for the purpose of affording a specimen for these experiments. 
< D ie specimen received was drawn out into two bars , A and B, under 
] the hammer , previously to which , however, two sections were filed on 
l the edges and a fracture made at each. Specific gravity 7.7397. 


Strength in pounds per 

square inch. 

» 

Point of fracture. 

REMARKS. 

58683 

No. 3 

Part in tin from 11£ to 15 Fracture near the wedges. 

57565 

“ 0£ 


60412 

“ 12f 

Broke in tin. 

65246 

“ 14$ 

Had been in tin at this point. 

65246 

« 16$ 


63638 

“ 6$ 


65079 

Sh 


66482 

“ 9| 

Near the tinned part. 

64392 

“ 5# 

Had not been in or near the tin. 



The mean area of the 9 sections of fracture is .000099 square 


V 

inch greater than that of the 19 sections measured before trial. 

and breaking it at each. 



This section was filed very deep before the bar had been re- 

58459 


duced to uniform size. 

61925 


Filing much less than in the preceding section. 


















194 


TABLE LXXXI. 


Experiments on bar No. 218 B. Manufactured by the Salisbury Iron Company , 1 
at Salisbury , in Connecticut. The ore obtained from (i ore hill ” m that town. L 
The kind of metal used , “ dead gray pig.” Refined after the English method, j 


Marks. 

Breadth, 

Thickness. 

Areas before fracture. 

No. of the exp’t. 

DATE. 

Area of the section of 

fracture. 

Temperature, Fah. 

Breaking weight in 

the scale. 

Breaking weight X 

leverage. 

Friction. 

0 

.763 

.227 

.173206 


1833. 






1 

.761 

.227 

.172747 

1 

April 27, 

.174269 

580° 

326 

9780 

489 

2 

.761 

.226 

.171986 








3 

.761 

.227 

.172747 








4 

.761 

.227 

.172747 

2 

<< 

.174879 

96 

341 

10230 

511 

5 

.761 

.227 

.172747 








6 

.761 

.229 

.174269 








7 

.761 

.230 

.175030 

3 

a 

.175030 

90 

346 

10380 

519 

8 

.761 

.230 

.175030 








9 

.761 

.230 

.175030 








10 

.761 

.230 

.175030 

4 

<< 

.174840 

74.5 

360 

10800 

540 

11 

.761 

.230 

.175030 








12 

.761 

.229 

.174269 








13 

.761 

.230 

.175030 

5 

u 

.174840 

74 

371 

11130 

556 

14 

.761 

.230 

.175030 








15 

.762 

.229 

.174498 








16 

.762 

.230 

.175260 

6 

May 2, 

.175030 

77 

400 

12000 

600 

17 

.761 

.229 

.174269 








18 

.761 

.229 

.174269 








18.3 

.762 

.230 

.175260 

7 

U 

.172747 

77 

400 

12000 

600 


Mean of 20 .174173 












8 

U 

.172747 

77 

400 

12000 

600 


Maximum .175260 









Minimum 

.171986 











— 

9 

u 

.172747 

77 

398 

11940 

597 


Mean of ihe2 .173623 









Diff. of the 2 .003274 


J 










10 

u 

.175030 

77 

398 

11940 

597 





Mean of 10 

.174186 







































195 


TABLE LXXXI. 


A loup made, and a gun bar formed expressly for the purpose of affording a 
specimen for these experiments. Drawn under the hammer, reduced by filing, and 
gauged at every inch from 0 to 18 3-10 inclusive . Specific gravity, 7.7397. 


Effective strain. 

Strength in lbs. per 
square inch. 

Point of fracture. 

REMARKS. 

9291 

53314 

No. 1 

In tin from 3 to 6j. 

9719 

55575 

“ 15* 

\ 

9861 

56339 

“ 14 


10260 

58682 

“ 12| 


10574 

60478 

“ 11* 


11400 

65132 

“ 10 


11400 

65992 

“ 5 

Broke without additional weight. 

11400 

65992 

“ 3* 

Had been in tin. 

11343 

65662 

« 1 


11343 

64806 

H* 

00 

V* 

Mean area of 10 seciions of fracture is greater than 
that of 20 measured sections by .000013. 


17 
















196 


TABLE LXXXII. 

Experiments on bars No. 219 A and 219 B. Manufactured by the'] 
Salisbury Iron Company , at Salisbury , in Connecticut , the ore obtain- ^ 
ed from u Ore Hill” in that town. The hind of pig used , lively ( 
gray. Refined after the English method. A loup made and a gun J 


Marks. Bai • No. 219 A. 

Breadth. 

Thickness. 

Area of the measured 
sections before trial. 

Marks. 

Breadth. 

Thickness. 

Area after trial. 

No. of the experiment. 

0 

.754 

.200 

.150800 







1 

.757 

.197 

.149129 







2 

.759 

.198 

.150282 

.150643 

.150842 






1 

3 

4 

.757 

.758 

.199 

.199 

Meas. after the 9th exper’t. 

5 

.756 

.196 

.148176 

5 

.713 

.168 

.119784 


6 

.754 

.196 

.147784 

6 

.713 

.187 

.133331 


7 

.755 

.197 

.148735 

7 

.717 

.189 

.135513 

2 

8 

.755 

.197 

.148735 

8 

.722 

.190 

.137180 

3 

9 

.755 

.197 

.148735 

9 

.726 

.186 

.135036 

4 

10 

.755 

.196 

.147980 

10 

.723 

.188 

.135924 

5 

11 

.752 

.197 

.148144 

11 

.714 

.188 

.135232 

6 

12 

.753 

.197 

.148341 

12 

.711 

.186 

.132246 

7 

13 

.755 

.198 

.149490 

13 

.712 

.183 

.130296 

8 

14 

.755 

.197 

.148735 

14 

.701 

.180 

,126180 


15 

.756 

.196 

.148176 






9 

16 

.756 

.195 

.147420 

16 

.670 

.175 

.117250 


17 

.758 

.196 

.148568 

17 

.715 

.185 

.132275 

10 

18 

.757 

.197 

.149129 

18 

.720 

.188 

.135360 


19 

.757 

.196 

.148372 

19 

.721 

.187 

. 

134827 

11 

20 

.757 

.193 

.146101 







21 

.756 

.192 

.145152 






12 

22 

.756 

.195 

.147420 







23 

.757 

.196 

.148372 






13 

24 

.755 

.198 

.149490 







25 

.757 

.197 

.149129 




* 



26 

.754 

.194 

.146276 







26.4 

.753 

.196 

.147588 










J .148478 







Mean ol at 



Breadth. 

Thick. 



Maximum . 150842 
Minimum . 145154 



.746 

.751 

.199 

.196 

1 

2 

Mn. of the 2 .147998 



.729 

.192 

3 

Diff. of the 2 .005688 








DATE. 

Area of the section of 

fracture before trial. 

Temperature, Fah. 

Breaking weight in 

| the scale. 

Breaking weight x 

leverage. 

1833. 


o 



Jan.26, 

.145626 

63 

267 

8010 

<c 

.147227 

50.5 

307 

9210 

44 

.146286 

55.5 

309 

9270 

Feb. 2, 

.150742 

596 

306 

9180 

44 

.148176 

630 

312 

9660 

44 

.147236 

59 

324 

9720 

«( 

.147420 

60 

341 

10230 

* 4 

.150382 

60 

320 

9600 

Feb. T, 

.148176 

574 

335 

10050 

44 

.149238 

54 

351 

10530 

u 

.148242 

54 

355 

10650 

“ 

.148735 

60 

361 

10830 

u 

.148016 

65 

367 

11010 

a 

.148454 

572 

347 

10410 

a 

.147196 

65.25 

339 

10170 

(< 

.139968 

* 

65 

333 

9990 



















































197 


TABLE LXXXII. 

fbar formed for these experiments. Drawn under the hammer , and bar 
) A. reduced to a uniform size by filing. Bar B. filed deeply at three 
} several points and broken at each filing. Specific gravity 7.8004. 




D 

8 






ho 




.s 

s 

CO 

£ 

d 

s 

‘3 

3 

S«« j 
jid >.s 

s 2 u 2 

r6 

u 

3 

Friction. 

4-» 

GO 

> 

• M 

w 

o 

w 

XX 

be a 
H.S 

u £ 

O 

E. 

w 

'So s 
‘3.2 

£> eo 
9+ S 

Extension 
'fore the fir 
liile the ba 
;ved from st 

a 

3 

c 

•* *-> 

3 

O 

C-. 



CO 

<b 

X S'-S 






fllS 

1st percept."' 






203 

.50 in 24 






215 

225 

.78 “ 

1.00 « 

No. 

400 

7610 

52257 


235 

1.27 « S 

20* 




244 

1.60 





252 

1.89 « 






260 

2.44 « 






267 

2.51Broke. 







J 


460 

8750 

59418 



25| 

463 

8807 

60204 



21* 

459 

8721 

57854 



34 

468 

8892 

60010 



15 

486 

9234 

62036 



19* 

511 

9719 

65903 



16 

480 

9120 

60645 



o* 

502 

9548 

64437 

• 



5 

526 

10004 

67033 



13* 

532 

10118 

68253 



11* 

541 

10289 

69175 



71 

73 

550 

10460 

70668 



9 r 

$ 

520 

9890 

66620 




508 

9662 

65640 




499 

9491 

67808 





REMARKS. 


Broke at the smallest section in the bar. 


Part in tin from 13* to 17. 
Broke in tin at the hottest part. 


Broke near the wedges, part in tin from 

* to 10*. 

Fracture farthest point from the part heated 
i the last experiment. 

Part last in tin not yet broken. 

This part was in the packing at the last 
cperiment in hot metal. 

Had been in tin at 574°. 

The mean area of the 13 sections of fracture 


Broke in tin. 
Cold fracture. 
Do. 






































19S 


TABLE LXXXIII. 

Experiments on bar No. 220 A. Manufactured by the Salisbury "'j 
Iron Company, at Salisbury, in Connecticut. The ore obtained from [ 
“ Ore Hill,” in that town. The kind of pig used, mottled. Re- { 
fined after the English method. A loup made, and a gun bar formed J 


Mean of 31 .163755 


Maximum 

Minimum 


.164808 

.162854 


Mn. of these 2 .163831 
Diff. of tlie 2 .001954 


16 

17 

18 

19 

20 
21 


Mar. 2, 

(C 


ii 

u 

44 

44 


163728 

.163782 

.163400 

.163776 

.163322 

162907 


59.5 

59.5 

60.5 
60.5 
61. 
61. 


Mean of 21 .163755 


Marks. 

Breadth. 

Thickness. 

Area before trial. 

! 

Marks. 

Breadth. 

Thickness. 

Area after trial. 

No. of the experiment. 

DATE. 

Area of the section of 

fracture before trial. 

T emperature, Fah. 

Breaking weight in 

the scale. 

0 

.762 

.215 

.163830 

Measured after exp’t. 9th. 


1833. 




1 

.762 

.215 

.163830 

10 

.702 

.194 

.136188 

1 

Feb. 23, 

.163400 

69.5° 

301 

2 

.762 

.216 

.164592 

11 

705 

.197 

.138885 






o 

O 

.763 

.215 

.164045 

12 

.710 

.198 

.140580 

2 

6i 

.164045 

49.5 

300 

4 

.763 

.216 

.164808 

13 

.707 

.198 

.139986 






5 

.763 

.215 

.164045 

14 

.705 

.196 

.138180 

3 

U 

.163615 

49.5 

310 

6 

.762 

.215 

.163830 

15 

.709 

.199 

.141091 






7 

.762 

.215 

.163830 

16 

.711 

.199 

.141489 

4 

U 

.163400 

620. 

335 

8 

.760 

.215 

.163400 

17 

.716 

.200 

.143200 






9 

.760 

.215 

.163400 

18 

.704 

.197 

.138688 

5 

a 

.163830 

650. 

363 

10 

.760 

.216 

.164160 

19 

.720 

.200 

.144000 






11 

.762 

.216 

.164592 

20 

.721 

.200 

.144200 

6 

Feb. 28, 

'.163830 

60. 

384 

12 

.759 

.215 

.163185 

21 

.718 

.199 

.142882 






13 

.758 

.216 

.163728 

22 

.713 

.198 

.141174 

7 

U 

.164426 

55. 

386 

14 

.759 

.216 

.163944 

23 

.706 

.196 

.138376 






15 

.760 

.215 

.163400 

24 

.708 

.197 

.139476 

8 

U 

.164299 

'55. 

386 

16 

.763 

.215 

.164045 

25 

.703 

.195 

.137085 






17 

.762 

.214 

.163068 










18 

.761 

.214 

.162854 

After experiment 12. 

9 

u 

.164211 

55. 

391 

19 

.762 

.214 

.163068 

12 

.701 

.199 

.139499 






20 

.762 

.215 

.163830 

13 

.700 

.198 

.138600 






21 

.762 

.215 

.163830 

14 

.696 

.197 

.137112 

10 

u 

.164448 

580. 

344 

22 

.762 

.215 

.163830 

15 

.693 

.194 

.134442 






23 

.761 

.215 

.163615 





11 

u 

.163507 

580. 

345 

24 

.760 

.215 

.163400 










25 

.761 

.215 

.163615 

18 

.673 

.190 

.127870 

12 

a 

.163556 

575. 

350 

26 

.760 

.215 

.163400 

19 

.708 

.200 

.141600 






27 

.762 

.215 

.163830 

20 

.710 

.198 

.140580 

13 

u 

.163780 

56.5 

354 

28 

.763 

.215 

.164045 

21 

.710 

.197 

.139870 






29 

.763 

.215 

.164045 

22 

.704 

.201 

.141504 

14 

u 

.164376 

57.5 

354 

29.6 

.760 

.215 

.163400 

23 

.698 

.193 

.134714 

15 

it 

.163321 

58.5 

372 


372 

372 

368 

368 

381 

381 






















































199 


TABLE LXXXIII. 


t 


'expressly for these experiments. Brawn under the hammer , 
by filing, and gauged at every inch from 0 to 26.6, inclusive, 
gravity , 7.7855. 


reduced 

Specific 


Weight X leverage. I 

i 

| Friction. 

Effective strain. 

Strength in pounds 

per square inch. 

Point of fracture; 

REMARKS. 

9030 

451 

8579 

52503 

No. 9 

C A part not included in the first experiment, the 

9000 

450 

8550 

52119 

“ 29 

•s bar being- too long to be taken all at once into the 
C machine. 

9300 

465 

8835 

53999 

“ 26! 

r Part in tin from 3! to 6. After this experiment, 

10050 

502 

9548 

58433 

« 8 

< sent the bar forward and took hold again, without 
C changing the tin. 

10890 

544 

10346 

63151 

“ 7 

Broke at the coldest part. 

11520 

576 

10944 

66801 

“ 6 


11580 

579 

11001 

66905 

“ 4! 


11580 

579 

11001 

66958 

“ 3! 

r This section of the bar is now finished. Part 

11730 

586 

11144 

67864 

“ H 

< from 9 to 26! was then gauged again. This sec¬ 
tion had not been in tin. 

10320 

516 

9804 

59618 

“ 10 | 

Broke near the wedges. Part in tin from 15 to 18!. 

10350 

517 

9833 

60138 

“ 24! 

Broke near the wedges. 

10500 

525 

9975 

60988 

“ 16! 

Broke in the tin. 

10620 

531 

10089 

61601 

“ 9! 

Within the gripe of the wedges. 

10620 

531 

10089 

61378 

“ 10 i 

Do. do. 

11160 

558 

10602 

64915 

“ 12 | 


11160 

558 

10602 

64754 

“ 13 


11160 

558 

10602 

64610 

“ 13| 

Near the wedges. 

11040 

552 

10488 

64186 

“ 24 

Remote from tinned part. 

11040 

552 

10488 

64039 

“ 22! 

11430 

571 

10859 

66488 

“ 19g 


11430. 

571 

10859 

56658 

“ 18! 

The mean area of the 21 sections ot fracture is 
identical with that of the 31 measured sections. 


17 * 





























200 


TABLE LXXXIV. 

Experiments on bar No. 220 B. Manufactured by the Salisbury 
Iron Company , at Salisbury , Connecticut. The ore obtained from “Ore ^ 
Hill,” in that town. The kind of pig employed , the mottled. Refined ( 
after the English method. A loup made and a gun bar formed J 


2 

3 

4 

5 

6 

7 

8 
9 

10 

11 

12 

13 

14 

15 

16 

17 

18 

19 

20 
21 
22 - 

23 

24 

25 

26 

27 

28 
29 


0 ) 

U 

a 

& 


a 

QJ 

« 


.752 
.756 
.756 
.756 
.756 

752 
754 
757 

.754 
.756 
756 

753 

754 
.754 
.754 
.756 
.754 
.754 
.754 
.754 
.754 
.754 
754 
.754 
.752 
.753 
.753 
.753 
.753 
753 

30.752 

Mean of 27 
Maximum 
Minimum 
Mn. of the 2 
)iff. of the 2 


2 

•fi 

+-> 

4* 

<2 

Cl 

-C 

M 

« 

o 

S 

o 

£ 

h 


.220 

218 

.218 

.216 

.217 

217 
.217 
219 

218 
.218 
.218 
.218 
.218 
218 
218 
218 
218 
218 
219 
218 
.219 
218 
219 
219 
.219 
.219 
.219 
.218 
.219 
.219 
.219 


Area before trial. 

Marks. 

Breadth after trial. 

Thickness after trial. 

r 

Area after trial. 

I No. of the exp’t. 

DATE. 

Areas of section of 

fracture before trial. 

Temperature, Fall. 

Breaking weight in 

the scale. 

Breaking weight X 

leverage. 

.165440 

Measures 

takei 

i after the 







.164808 

first 

No. 

expen 

nent. 



1833. 


o 



.164808 

5 

.697 

.199 

.138703 

1 

Feb. 21, 

.163296 

63.5 

336 

10080 

.163296 

Sit 

tallest 

at begi 

lining-. 







.164052 

8 

.7191.2081 .148833 

• 






.163184 

Largest at beginning. 







.163618 

24f| .697 

.197 

.137309 







.165783 

Smallest section at present. 

2 

<c 

.164797 

575 

336 

10080 

.164372 











.164808 











.164808 





3 

U 

.164749 

62.5 

336 

10080 

.164154 











.164372 





4 

«( 

.164749 

576 

347 

10410 

.164372 











.164372 





5 

(i 

.164907 

572 

361 

10830 

.164808 





6 

u 

.164749 

580 

371 

11130 

.164372 





7 

n 

.164530 

67 

389 

11670 

.164372 





8 

Feb. 23, 

.164907 

67 

394 

11820 

.165126 





9 

(( 

.165126 

67 

397 

11910 

.164372 

Measurements taken after 

10 

44 

.164797 

67 

397 

11910 

.165126 

the sixth experiment. 







.164372 

21 

.6821 

.196 

.133672 

11 

44 

.165124 

71.5 

360 

10800 

.165126 

22 

.697 

.200 

.139400 







.165126 

23 

.677 

.196 

.132692 

12 

(< 

.163329 

550 

364 

10920 

.164688 

24 

.665 

.191 

.127015 







.164907 

25 

.668 

.193 

.128924 

13 

it 

.164808 

590 

364 

10920 

.164907 

26 

.707 

.200 

.141400 







.164154 

27 

.71? 

.206 

.147702 

14 

tt 

.165077 

61 

388 

11640 

.164907 

28 

.713 

.203 

.144739 

15 

H 

.164481 

61 

371 

11130 

.164907 





16 

(( 

.164590 

61.25 

385 

11550 

.164688 





17 

<( 

.164372 

61.25 

385 

11550 

.164587 





18 

<( 

.164372 

61.25 

393 

11790 

.165783 

.173184 






Mn. of 18 

.164598 




.164483 











.002599 1 




. 








\ 






















































201 


TABLE LXXXIV. 

\ 


f expressly for these experiments. Drawn under the hammer , reduced by 
J filing to a nearly uniform size and gauged at every inch, from 0 to 30. 
] Specific gravity , 7.7855. 




c 

o< 

« 

<V 

to 

E — 

D % 

I 




c 
• <■* 


V 


s 

a 

C J 

5 - « 

3 


"o3 

O 

•d 

o 

& 

o 

Friction. 

V) 

V 

a a 

u 

P« 

w S 
§2 

& 

► 

• N 

W 

O 

tc 

W 

# s 

bO 

G V 

s % 

u 2 
c/7 cr 1 

Weights 

longation. 

V ^ 
cs 

to i. 

G > 

O V 

u 

o 

w 

P 

£ 




180 

1st perman. 

No. 




\ 184 

1-40 in. in 24 / 

504 

9576 

58642 

< 284 
/ 289 

24 bee. 26.5 > 

“ 27. \ 

3 




336 

Broke. J 


504 

9576 

58108 



294 

504 

9576 

58125 



174 

520 

9890 

60030 



19| 

541 

10289 

62393 



284 

556 

10574 

64182 



204 

583 

11087 

67386 



274 

591 

11229 

68093 



26 

595 

11315 

68523 



22 

595 

11315 

68660 



24^ 

540 

10260 

62135 



0 i 

546 

10374 

63516 




546 

10374 

62946 



10 

582 

11058 

66987 



n 

556 

10574 

64287 



10 i 

577 

10973 

66669 



154 

577 

10973 

66757 



134 

589 

11201 

68144 

1 


124 


REMARKS. 


f The bar was too long to be all put in. Took 
| the part between 0 and 24 being the most 
uniform—the first elongation was under 
23-48 of the breaking weight.—Very uni 
Jormly stretched. 

C In tin from 23^ to 26|. Broke near the 
| wedges,—this part not strained in the first 

t experiment. Broke very soon under the 
same weight as before—probably would 
have broken with a little less. 

Weight put on gradually. 

From 224 to 25$ now in tin. Broke near 
the wedges. 

Fracture at the opposite end to the preceding. 
Broke at the opposite end to the preceding 
Opposite end to the preceding. 

Same end as the preceding. 

Opposite end to the preceding. 

Til’s exper. finished this part of the bar. 

Not heated. Piece broken off in first exp. 

C Piece now in from 3 to 174- Part in tin from 8 
to 12. Greatest wt, previously borne 336. 
C Broke in tin with the same weight as it 
(_ bore in the preceding experiment. 

Part now tried from 54 to 10. 

Part now in from 10 to 174- 

Do. from 104 to 174- 

Do. “ 104 to 15£. 

Do. “ 104 to 134* 

The mean area of 18 sections of fracture is 
.000011 square inch greater than that of the 
31 measured sections. 


i 
























202 


TABLE LXXXV. 

Experiments on bar No. 221 A. Manufactured by the Salisbury"} 
Iron Company, at Salisbury, in Connecticut. The ore obtained from I 
“ Ore Hill” in that town. The kind of metal employed, “ white pig,” [ 
—refined after the English method. A loup made and a gun bar J 


Marks. 

Breadth. 

Thickness. 

i 

Areas before trial. 

No. of the exp’t. 

DATE. 

Area of the section 
of fracture before trial. 

< 

Temperature, Fah. 

Breaking weight in 

the scale. 

Breaking weight X 

leverage. 

Friction. 

Effective strain. 

1 

.757 

.224 

.169568 


1833. 


o 





2 

.752 

.227 

.170704 

1 

Mar. 14, 

.170931 

570. 

318 

9540 

477 

9063 

3 

.754 

.229 

.172666 









4 

.752 

.228 

.171456 

2 

U 

.172060 

580. 

381 

11430 

571 

10859 

5 

.753 

.229 

.172437 









6 

.753 

.229 

.172437 









7 

.753 

.228 

.171684 

3 

u 

.171031 

520. 

362 

10860 

543 

10317 

8 

.753 

.228 

.171684 









9 

.753 

.229 

.172437 









10 

.753 

.229 

.172437 

4 

u 

.172186 

73. 

404 

12120 

606 

11514 

11 

.753 

.227 

.170931 









12 

.753 

.227 

.170931 

5 

u 

.172437 

72. 

404 

12120 

606 

11514 

13 

.752 

.227 

.170704 









14 

.753 

.228 

.171684 

6 

« 

.169947 

71.5 

404 

12120 

606 

11514 

15 

.753 

.228 

.171684 









16 

.753 

.227 

.170931 

7 

it 

.171456 

71. 

404 

12120 

606 

11514 

17 

.751 

.228 

.171228 









18 

.752 

.227 

.170704 

8 

Mar. 16, 

.170931 

78.5 

377 

11310 

565 

10745 

19 

.753 

.227 

.170931 









20 

.753 

.227 

.170931 

9 

U 

.171684 

78. 

380 

11400 

570 

10830 

21 

.753 

.227 

.170931 









22 

.753 

.227 

.170931 









23 

.753 

.227 

.170931 

10 

U 

.170931 

78. 

380 

11400 

570 

10830 

24 

.753 

.228 

.171684 









25 

.753 

.228 

.171684 









9 « 6 

.752 

.228 

.171456 

11 

u 

.170931 

t 

77. 

392 

11760 

588 

11172 

Mean of 26== 

.171376 

12 

<6 

.170817 

77. 

392 

11760 

588 

11172 

Maximum= 

.172666 

13 

a 

.170966 

76.5 

401 

12030 

601 

11429 

Minimum = 

.169568 













14 

a 

.179931 

76. 

394 

11820 

591 

11229 

Mn. of these 2 

.171117 












- . — 

Mean of 14 

.171231 






Diff. of the 2 .003098 





















































203 


TABLE LXXXV. 

fformed expressly for these experiments. Drawn under the hammer, 
J subsequently reduced by fling to a nearly uniform size , and gauged 
] at every inch. Specific gravity , 7.8018. 


tli in lbs. per 

ich. 

<V 

a 

■*-> 

o 

& 

REMARKS. 

u~ 

G K 

_ a 
(A 3 

ST 

CO 

o 

■*-> 

.s 

o 


53021 

No. 21 

Part in tin from 2 * to 5*. 

63111 

“ 8 * 

0 Same part in tin. Temperature had been as high as 600° 
for a short time. 

60322 

“ 13* 

^ Broke in tin. Part immersed from 13 to 16, inclusive. Had 
been strained in experiment No. 1 . Temperature had been 550°. 

66869 

“ 65 

0 Part left in experiment 2d., which did not break in tin. 
£ Now broke at a part which was of a straw colour. 

66772 

“ 5 

Broke with the same weight as above. 

67750 

<< u 

J -3 

Bore the weight a moment, and then gave way. 

67154 

“ 4 

Bore the weight a short time. 

62862 

“ 22 | 

This part was broken off in experiment No. 1 . 

63081 

“ 25 

Do. 

63358 

“ 19 

C The weight is supposed to have been too great. The 
< whole weight employed in the last experiment put on by 
C mistake. The bar broke immediately. 

65359 

“ 20 


65403 

“ 18* 

Gradually gave way under the same weight as the preceding. 

66849 

" 17* 


65693 

“ 11 * 

A different, piece from the preceding. 

The mean area of the 14 sections of fracture is .000145 square 
inch less than that of the 26 measured sections. 














204 


TABLE LXXXVI. 

Experiments on bar No. 221, B. Manufactured by the Salts- 
bury Iron Company , at Salisbury in Connecticut. The ore { 
obtained from “Ore Hill” in that town. “White pig” metal , \ 
refined after the English method,—a loup formed and a “ gun J 


Marks. 

Breadth. 

Thickness. 

Area at the sections 
measured before trial. 


No. of the experiment. 

DATE. 

Area of the section of 

fracture before trial. 

j Temp. Fah. 

Breaking wht. in the 

scale. 

Breaking weight [x 

leverage. 

Friction. 

Effective strain. 

1 

.762 

.232 

.176784 



1833. 


o 





2 

.753 

.229 

.172437 


1 

Mar. 21, 

.174347 

576 

335 

10050 

502 

9548 

3 

.753 

.229 

.172437 










4 

.753 

.229 

.172437 


2 

u 

.173387 

574 

341 

10230 

511 

9719 

5 

.754 

.229 

.172666 










6 

.753 

.230 

.173190 


3 

u 

.172437 

576 

378 

11340 

567 

10773 

7 

.754 

.231 

.174174 










8 

.755 

.231 

.174405 










9 

.754 

.229 

.172666 










10 

.755 

.229 

.172895 


4 

Mar. 23, 

.173420 

576 

392 

11760 

583 

11172 

11 

.755 

.230 

.173650 










12 

.755 

.230 

.173650 


5 

u 

.173420 

576 

402 

12060 

603 

11457 

13 

.755 

.230 

.173650 










14 

.754 

.230 

.173420 










15 

.754 

.230 

.173420 


6 

(t 

.173928 

100 

410 

12300 

615 

11685 

16 

.755 

.230 

.173650 










17 

.755 

.230 

.173650 










18 

.754 

.230 

.173420 


7 

u 

.174289 

90 

416 

12480 

624 

11856 

19 

.755 

.230 

.173650 










20 

.756 

.229 

.173124 


8 

a 

.173101 

68 

425 

12750 

637 

12113 

21 

.755 

.230 

.173650 










22 

.755 

.231 

.174405 


9 

u 

.173147 

68 

425 

12750 

637 

12113 

23 

.755 

.231 

.174405 

Unfiled por- 









24 

.754 

.231 

.174174 

tion near the 

10 

a 

.173650 

68 

425 

12750 

637 

12113 

25 

.752 

.232 

.174464 

end. 

Br. Th. 


t 







25,6 

.755 

.232 

.175160 

.850| .227 

11 

u 

.192950 

68 

392 

11760 

588 

11172 

Mean of 26 .173682 















12 

a 

.173124 

67 

375 

11250 

562 

10688 


Maximum . 176784 











Minimum 

.172437 















13 

ti 

.174812 

66 

375 

11250 

562 

10688 

Mean of the 2.174610 

• 









Diff. of the 2 

.004347 



Mn. of 12 = 

.173589 






































205 


TABLE LXXXVI. 


" bar” drawn expressly for these experiments, 
hammer into two bars , each reduced by filing 
) and then marked and gauged at every inch. 

I 7.8018. 


Drawn under the 
to a uniform size, 
Specific gravity , 


u 

A 

■ 

-D 

• 

<L> 

3 

CJ 


Strength ii 
sq.inch. 

C 3 

C 

«*- 

o 

w 

.5 

o 

REMARKS. 

54764 

No. 23i 

Part in tin from 3 to 6£. 

56054 

62475 

*• 191 

“ 4 

Same part still in tin. 

C Took hold of the bar near the pan of melted metal, leaving a 
< part for future experiment, and compelling it to break in or 
C near the hottest part. Fracture within the tin. 

64421 

66065 

“ 18 

“ 14i 

C Part in tin from 12 to 15^ which had been tried in the second 
£ experiment—fracture near the end. 

% 

Broke in the tin. 

67183 

“ 6| 

r The part now put in is from 4 to 14, both ends of which 
< have been broken in tin at 576°. Fracture took place out- 
C. side of where it had been in the tin. 

68025 

“ 7i 

Broke at a part which had been less heated than the preceding. 

69976 

“ 8| 

Had not been in tin. 

69958 

“ 10J 

Had been near the tin. 

69755 

57901 

“ iii 

“ unc. 

Do, This part of the specimen is now finished. 

C Part now in the machine is from 1 to 4. The unfiled pari 
£ being in the wedges, the fracture took place at that part. 

61736 

“ 20 

C Short piece.—Had been between two former cold fractures 
( in experiment second. 

61140 

“ 25£ 

C This piece had likewise been tried only at a cold fracture in 
£ experiment first. No additional weight was required. 

The mean area of the 12 sections of fracture on the filed 
part was .000093 square inch less than that of the 26 measured 
sections. 
















206 


TABLE LXXXVII. 


Experiments on ar No. 222 A. Manufactured by the Salisbury 
Iron Company, at Salisbury in Connecticut. The ore obtained from 
“Ore Hill,” in that town. The metal, a mixture of “ dead gray,” “ lively 
gray,” “ mottled,” and “ white ” pigs, refined after the English me¬ 
thod, a loup formed and a gun bar drawn expressly for these experi- 


> 


Marks. 

Breadth btfoie tri a). 

Thickness before trial. 

Areas of the measured 
sections before trial. 

Marks. 

Breadths after trial. 

Thickness after trial. 

Areas after trial. 

< 

No. of the experiment. 

1 

DATE. 

Area of the section of 

fracture. 

Temperature, Fahren¬ 

heit. 

Breaking weight in the 

0 

.766 

.221 

.169286 










1 

.759 

.219 

,166221 






1833. 


o 


2 

.759 

.219 

.166221 





1 

Mar. 21, 

.168942 

560 

294 

3 

.761 

.218 

.165898 










4 

.762 

.219 

.166878 










5 

.762 

.220 

.167640 

M( 

;asures 

taken 

after the 






6 

.761 

.221 

.168181 

4th experiment. 


2 

<( 

.169286 

73.5 

350 

7 

.762 

.222 

.169164 

1 

.728 

.209 

.152252 






8 

.764 

.222 

.169608 

2 

.735 

.207 

.162145 






9 

.762 

.222 

.169164 

3 

.730 

.209 

.152570 






10 

.762 

.222 

.169164 

4 

.726 

.207 

.150282 

3 

a 

.169164 

73.5 

360 

11 

.759 

.222 

.168498 

5 

.694 

.196 

.136024 






12 

.761 

.222 

.168942 

6 

.690 

.200 

.138000 

4 

a 

.168942 

73 

367 

13 

.761 

.222 

.168942 

6 $ 

.675 

.193 

.130275 






14 

.762 

.222 

.169164 

7 

.690 

.199 

.137310 

5 

<( 

.168402 

572 

348 

15 

.763 

.222 

.169386 

8 

.731 

.207 

.151317 






10 

.762 

.222 

.169164 

9 

.725 

.210 

.152250 

6 

Mar. 23, 

.169164 

75 

377 

17 

.761 

.222 

.168942 

10 

.730 

.210 

.153300 






18 

.761 

.222 

.168942 

11 

.730 

.211 

.154030 

7 

(t 

.168942 

75 

377 

19 

.761 

.222 

.168942 

12 

.720 

.206 

.148320 






20 

.762 

.221 

.168402 





8 


.168181 

75 

377 

21 

.761 

.222 

.168942 





9 

u 

.167497 

75 

377 

22 

.762 

.222 

.169164 





10 

(( 

.169164 

75 

377 

23 

.762 

.221 

.168402 





11 

u 

.168942 

67 

374 

24 

.762 

.220 

.167640 





12 

44 

.168402 

67 

374 

25 

.761 

.221 

.168181 





13 

u 

.168046 

67 

374 

26 

.762 

.221 

.168402 










27 

762 

.221 

.168402 





14 


.168497 

67 

374 

27*. 

762 

.221 

.168402 


















15 


168737 

67 

378 

Mean of 29 . 

168420 



















Mean of 15 

168686 



Maximum . 

169608 










Minimum . 

165895 










Mean of the 2 .167751 j 










Diff. of the 2.003713 | 






























































207 


TABLE LXXXVII, 

f merits. Drawn into two bars (A fy B.) Reduced to a uniform size 
j by filing , gauged at every inch from 0 to 27*, inclusive. Specific 
} gravity, 7.7555. 


• 

— 



, 

<b 

a. 






co 

<b 


To 


n 

* 

3 

«_> 


Cu 


£ 

rj 

ZJ 







REMARKS. 

hD 


V 


to 



3 

to 


O 


V 

i §? 

w 

o 

£ 

w 3 

o 


to v 
> 

to 

to 

C/7 3 

CJ* 

CO 

a. 




8379 

49597 

No. 

C Part in tin from 4 to 8. Temperature rose once 

8820 

441 

17 

(_ above 650°. 






r The temperature rose to 660° when the bar ap- 



9975 



peared to be breaking. Having allowed the tempera¬ 
ture to abate until it descended to 575°. Added 

10500 

525 

58924 

0 

<( weights until it appeared to be again breaking with 






335 lbs. in the scale. Some tin then escaped at 
the packing, and 15 lbs. more were required to 






_break it when cold. 

10800 

540 

10260 

60651 

14 


11010 

550 

10460 

61915 

12 * 


10440 

522 

9918 

58895 

27* 

Part in tin from 21 to 24*. 

11310 

5G5 

10745 

63518 

7 

Part under trial from 1 to 12. 

11310 

5G5 

10745 

63602 

io* 

C Section of fracture gauged after this experiment, 
l. 586 X- 153 = .089658. 

11310 

565 

10745 

63889 

6 


11310 

565 

10745 

64150 

4* 


11310 

565 

10745 

63518 

9* 


11220 

561 

10659 

63092 

18* 


11220 

561 

10659 

63295 

26 


11220 

561 

10659 

63429 

24* 


11220 

561 

10659 

63259 

22 | 


11340 

567 

10773 

63851 

20 | 

The mean area of 15 sections of fracture, is less than 
that of 29 measured sections by .000266 square inch. 


18 



























20S 


TABLE LXXXVIII. 

Experiments on bar JYo. 222 B. Manufactured by the Salisbury") 
Iron Company, at Salisbury, in Connecticut. The ore obtained from [ 
“ Ore Hill,” in that town. The metal was a mixture of “ dead gray,” \ 
“ lively gray,” “ mottled,” and “ white ” pig. Refined after the Eng-J 



-3 

CO 

CO 

<L> 

M 

1/3 

u 

■a 

as 

-2 

o 


Qj 



u 

p 

<< 

« 

r 1 

0 

.752 

.217 

1 

.757 

.217 

2 

.757 

.218 

3 

.757 

.219 

4 

.757 

.219 

5 

.756 

.219 

6 

.755 

.217 

7 

.754 

.216 

8 

.754 

.217 

9 

.755 

.219 

10 

.755 

.219 

11 

.757 

.220 

12 

.757 

.220 

13 

.756 

.221 

14 

.756 

.220 

15 

.756 

.220 

16 

.756 

.220 

17 

.755 

.220 

18 

.755 

.220 

19 

.755 

.220 

20 

.755 

.220 

21 

.754 

.218 

22 

.754 

.218 

23 

.754 

.218 

24 

.756 

.219 

25 

.756 

.220 

26 

.756 

.220 

27 

.756 

.220 

27.7 

.7561 

.219 


<u 

u 

CUT 


*3 <2 

o 4 , 

£ 2 
t 3 
< '«-> 

v 


.163184 

.164269 

.165026 

.165783 

.165783 

.165564 

.163835 

.162864 

.163618 

.165345 

.165345 

.166540 

.166540 

.167076 

.166320 

.166320 

.166320 

.166100 

.166100 

.166100 

.166100 

.164372 

.164372 

.164372 

.165564 

.166320 

.166320 

.166320 

.165564 


Mean of 29 .165425 


Maximum 

Minimum 


.167076 

.162864 


Mean of these 2 .164970 
Diff. of the 2 .004212 


1 

2 

3 

4 

5 

6 

7 

8 
9 

10 

11 

12 

13 

14 

15 

16 
17 


DATE, 


1833. 
Mar. 28, 


Si 


U 


Mar. 30, 


ii 


ii 


ii 


a 


a 


April. 4, 


ii 


a 


Cm 

O 

c as 

■M ’ • 

oo p 
■*- 

Cm ^ 
C 0) 
CJ ^ 

g 2 

< c3 
<2 


.166100 

.163455 

.166100 

.166320 

.163241 

.1^,3998 

.162864 

.165026 

.164267 

.165783 

.166100 

.165816 

.167076 

c 

.166540 

.165753 

.165236 

.164372 


Mean of 17 .165178 


03 

*\ 

p 

3 

■M 

03 

- 

Cn 

g 

S 

H 


fajo 




03 03 
C* 4) 
co 

tt O 


X 


pcs 

’53 


fcc 

G 

• M • 

^ 0) 
a 6-0 
Cy ce 

K £ 


c 

o 


560.° 

298 

8940 

447 

576. 

308 

9240 

462 

566. 

320 

9600 

480 

554. 

348 

'10440 

522 

566. 

349 

10470 

523 

66. 

349 

10470 

523 

66. 

374 

11220 

561 

65. 

374 

11220 

561 

65. 

375 

11250 

562 

65. 

375 

11250 

562 

554. 

332 

9960 

498 

578. 

345 

10350 

517 

64. 

369 

11070 

553 

64.5 

370 

11200 

555 

75.5 

374 

11220 

561 

74. 

369 

11070 

553 

74. 

369 

11070 

553 

















































20.9 


TABLE LXXXVIII. 

Clish method . Ji loup formed and a gun bar drawn , expressly for 
j these experiments. Reduced to a nearly uniform size by filings and 
) gauged at every inch from 0 to 27.7. Specific gravity , 7.7555. 



3 

A 




c 

Cft 

£ 


"3 


C3 

U 

s 


w 


Qj 

—< 


a 

03 

REMARKS. 

O 

&C.£ 

c 




tc 

U 

a 


*3 


W 

CO 3 
o - 

CO 




8493 

51132 

No. 

He* 

00 

T-l 

Part in tin from 5£ to 9. 

8778 

53703 

a 

o* 

Broke near the wedges. 

9120 

54907 

ic 

14 

0 Broke near the wedges on the opposite side of 
£ tin bath. 

9918 

59632 

a 

15i 

Do. 

9947 

60934 

a 

4 

Broke in the tin. 

9947 

60653 

a 

0} 


10659 

65447 

u 

7 

Cut off the tinned part in the gripe of the wedges. 

10659 

64589 

u 

2 


10688 

65064 

a 



10688 

64469 

1C 

Si 


9462 

56966 

u 

20 

Part in tin from 22* to 25£. 

9833 

59301 

u 

24^ 

Broke in tin. Temp, had been as high as 614°. 

10517 

62947 

u 

13 

This part not heated. 

10545 

63318 

u 

11 


10659 

64389 

u 

24£ 

Part now under trial from 20 to 24£. ’ 

10517 

63649 

u 

20 £ 

• 

10517 

63983 

a 

24 

The mean area of the 17 sections of fracture is 
.000247 square inch less than that of the 29 measured 





sections. 














210 


TABLE LXXXIX. 

Comparative view of the influence of high temperatures on 
the strength of iron , as exhibited by 73 experimen ts on 47 differ¬ 
ent specimens of that metal, at 46 different temperatures , from 


No. of the comparison 

! 

Temperature observed 
at the moment of frac. 

Mark of the bar on 
which the trial was 
made. 

Strength at ordinary 
temperatures. 

No. of experiments at 
ordinary temperatures. 

Strength at the tem¬ 
perature observed. 

No. of experiments at 
high temperatures. 

Amount of variation 

from uniformity in the 

cold experiments. 

Effects of the heat ex¬ 

pressed in parts of the 
original strength. 

REMARKS. 

i 

212 ° 

137 

56736 

1 

67939 

1 


+ .197 


2 

214 

133 

53176 

1 

61161 

1 


+ .150 


3 

394 

58 

68356 

1 

71896 

1 


4 - -052 


4 

394 

148 

65143 

1 

69752 

1 


+ .070 


5 

394 

23 

62646 

2 

67765 

1 

.1041 

4 ~ *081 


6 

394 

125 

57182 

1 

63322 

1 


+ .107 


7 

394 

61 

55297 

5 

61917 

1 

.2026 

4- .119 


8 

396 

75 

60433 

3 

62415 

1 

.0444 

4 - .031 


9 

440 

224D. 

49782 

4 

59085 

1 

.0908 

4 - *187 


10 

520 

224B. 

54934 

4 

58451 

1 

.0992 

4- .064 


11 

550 

199A. 

76986 

4 

79846 

2 

.0936 

4-.037 


r The standard lor the 

12 

550 

221 A. 

60518 

4 

60322 

1 

.1680 

— .004 

J 

original strength may 

13 

552 

14 

52542 

1 

55932 

1 


4- .064 

1 

possibly be a little too 

14 

554 

218A. 

58124 

4 

60412 

1 

.0730 

4- .039 


Lhigh. 

15 

554 

22 

54372 

4 

61680 

3 

.1919 

4-.134 


16 

560 

224E. 

50528 

7 

58824 

1 

.0605 

4-.158 


17 

562 

224C. 

53385 

5 

59623 

1 

.1919 

4-.104 


18 

563 

60 

60907 

4 

72588 

2 

.0460 

4-.191 


19 

564 

74 

51030 

5 

58284 

1 

.0764 

4-.142 


20 

568 

9 

67211 

2 

76763 

1 

.0601 

4-.042 

C Standard probably 

21 

572 

219B. 

66724 

2 

66620 

1 

.0325 

— .002 

< too high for the mean 

22 

572 

49 

59607 

3 

62278 

1 

.0878 

4 - .045 

C strength. 

23 

572 

222 B. 

56165 

4 

60117 

2 

.1550 

4- .070 


24 

573 

10 

64511 

1 

67503 

3 


4 - .046 


25 

574 

231 

76071 

5 

65387 

1 

.1373 

4- .014 


26 

575 

220 A. 

54263 

4 

60988 

1 

.0280 

4- .124 


27 

575 

62 

58376 

3 

70081 

3 

.0262 

4 - .200 


28 

575 

207 

51924 

5 

63825 

3 

.1225 

+ .229 


29 

576 

221 B. 

59234 

5 

66065 

1 

.1190 

4- .115 


30 

576 

223 B. 

43386 

6 

50068 

*1 

.0760 

4 - .154 





























211 


TABLE LXXXIX. 

212° to 1317° Fall., compared with the strength of each bar when 
tried at ordinary temperatures, the whole number of experiments 
at the latter being 163. 


3 


O * 

M 

a. 

% 

r+ 

a. 

a 

.2 3 

.s 2 


M 

• 

3 

a* 

r* 

h a 

-2 '** 

0 O 

3 

o3 

-D 

s 

• H 

O 

-a 

W 

•M 

"•o 
^ > 

z 

A 

Ui 

•r .S 

aj . oo 

a 

g’j? 

^ o 

V 


o 

V 

V 

w 

o 

o’ 

Z 

oj 

*■* H* 

3 4, 
w £ 

2 5 
0.3 

3 V 

3*5 

w 

Mark of th 
which the t 
made. 

Strength at 
temperature. 

03 

i 

X 

D 

O 

d 

■M 

* 2 
aa-§ 

tuO u 

c ^ 

£ 3 

w C3 

c/: 

<L> 

o, 

i 

X 

a 

o 

» 

Cm'S 32 

° c.1 

s-t® C 
c t: « 

3 s a. 

O 3 * 

p a 

5 S-d 

C o-r 
l. o 

Cm V 

Effects of th 

parts of the 

strength. 

REMARKS. 

31 

°577 

164 

58769 

5 

66929 

2 

.1214 

+.139 


32 

578 

224A. 

52406 

5 

59197 

1 

.0565 

+.129 


33 

578 

223A. 

45757 

5 

53465 

1 

.0896 

+.168 


34 

580 

86 

62156 

3 

77163 

2 

.0986 

+ .052 


35 

590 

220B. 

59459 

5 

62966 

1 

.0680 

+.058 


36 

598 

90 

50316 

5 

57310 

2 

.2401 

+.138 


37 

630 

219A 

59530 

4 

60010 

1 

.1440 

+.008 

C This experiment was on a 

38 

636 

16 

53543 

1 

50039 

1 

.1563 

—.067 

(_ part probably defective. 

39 

662 

150 

59307 

5 

58181 

1 

.0644 

—.019 

40 

722 

152 

57133 

3 

54441 

1 

.0507 

—.047 


41 

732 

14 

52542 

1 

53378 

1 

.1310 

+.016 


22 

734 

150 

59397 

1 

57903 

1 

.0644 

—.026 


43 

766 

16 

56891 

1 

54819 

1 

.1563 

—.037 


44 

r 770 
^ 824 
)and 
(814 

825 

149 

56825 

2 

54781 

1 

.0234 

—.036 


45 

214 

59219 

1 

55892 

1 

.0413 

—.073 


46 

149 

56825 

2 

56644 

1 

.0234 

— 029 


47 

932 

214 

59219 

1 

45531 

1 

.0413 

— 240 


78 

947 

232 

58341 

2 

42401 

1 

.0446 

—.273 


49 

1022 

214 

59219 

2 

37410 

1 

.0413 

—.369 


50 

1037 

152 

58992 

1 

37764 

1 

.0507 

—.360 


51 

1097 

227 

53426 

6 

27604 

1 

.0330 

—.483 


52 

1111 

227 

53426 

6 

27602 

1 

.0330 

—.483 

r The metal was decidedly defective at 
) the point where this fracture was made 
(.—flaws visible. 

53 

1142 

226 

54758 

2 

18672 

1 

.1147 

—.659 

54 

1155 

227 

53426 

6 

21967 

1 

.0330 

—.589 

t The 8th experiment on this bar being 
v taken as the standard would exhibit the 
( effect— .550. 

55 

1159 

229 

55774 

3 

25620 

1 

.1102 

—.538 

56 

1187 

227 

53426 

6 

21910 

1 

.0330 

—.589 

57 

1235 

226 

54758 

2 

21298 

1 

.1147 

—.611 


58 

1245 

226 

54758 

2 

20703 

l 

.1147 

—.622 


59 

1317 

226 

54758 

2 

18913 

1 

.1147 

—. 654 




Mean 

57525 




i 


-- 


18* 




















212 


Effect of high temperature on iron. 

The experiments on bars of iron at high temperatures, were made either 
on sections deeply filed, or on those specimens which had been reduced by 
filing to a uniform size. 

The trials below 600° were chiefly conducted in a bath of oil, arranged 
round the bar as already represented in Plates Ill. and IV., and the temperatures 
marked by the mercurial thermometer. For temperatures above that point 
the bath of tin and lead was substituted, and, when necessary, the steam 
pyrometer took the place of the common thermometer. 

The view already presented of the influence of heat on copper, indi¬ 
cated partly by each of these two instruments, has enabled us to observe 
that they connect themselves in their indications in a manner to prove that 
no serious errors can be anticipated in the temperatures assigned in the 
higher parts of the scale when operating on iron. 

If, however, in examining the effect of temperature on copper we meet with 
some difficulties in consequence of the irregularities of structure in the mate¬ 
rial, of want of conformity in different bars, and of the occasional weaken¬ 
ing effects of alloying, on the total tenacity as we approach a red heat, the 
obstacles there encountered are comparatively trilling, when contrasted 
with those which are to be surmounted in the investigation of the effects of 
heat upon the tenacity of iron. Here we have, not only the variations due 
to the original composition of the metal; the differences resulting from the 
variety of pig-metal used in its manufacture, and the defects of the me¬ 
chanical structure, owing to the want of uniformity in welding, or of regu¬ 
larity in the temperature of working the bars ; but we have superadded 
to all these, a singular anomaly in the effect of heat itself on the tenacity 
of this material, which is believed never to have been before made the 
object of special inquiry. 

Notwithstanding these impediments, the committee have not felt au¬ 
thorized to leave so important a point of inquiry, without a faithful at¬ 
tempt to unravel its intricacies. It would have been easy to devise a set 
of experiments, which, for a theoretical purpose, might have afforded to 
the analyst some interesting problems, and probably served to clear the sub¬ 
ject of heat from certain difficulties with which its investigation is encum¬ 
bered. Such, however, was not the purpose in view of the committee. 

When we attempt to form a scale of the weakening effects of elevated 
temperatures, founded, as in the case of copper, on trials at ordinary tem¬ 
peratures, or even at the freezing point, we shall find that many of the first 
numbers in the scale will be negative, instead of positive, and this will con¬ 
tinue to different points of temperature, according to the nature or condition 
of the iron on which the experiments are made. In fact, some of the very first 
experiments at high temperatures rendered this manifest, by showing that on 
a bar of uniform size, the fracture would not take place within the heating 
bath ; and even that much filing of the part in the oil or melted metal, was 
necessary in order to prevent the fracture from taking place at unfiled sec¬ 
tions out of the hot hath rather than at the filed one in it. This circum¬ 
stance was noted at 212°, 392°, and 572°, rising by steps of 180° each 
lrom 32°, at which last point some trials had been made in melting ice. At 
the highest of these points, however, it was perceived that some specimens 
ol the metal exhibited but little, if any, superiority of strength over that 
which they had possessed when cold, while others allowed of being heated 


213 


nearly to the boiling point of mercury before they manifested any decided 
indication of a weakening effect from increase of temperature. 

It hence became apparent that any law, taking for a basis the strength of 
iron in its ordinary condition, and at common temperatures, must be liable 
to great uncertainty, in regard to its application to different specimens of 
the metal. It was evident that the anomaly above referred to, must be only 
apparent, and that the tenacity actually exhibited at 572°, as well as that 
which prevails while the iron is in the state in which it was left by forging, 
or rolling, must be below its maximum tenacity. To determine what ratio 
exists between the ordinary strength of a bar and its maximum strength 
when in the most favourable condition for resisting a longitudinal strain, 
experiments were made on several bars by heating them to 572°, and then 
applying weight enough to cause a fracture, either within or without the 
heated part. The bar was then taken out and allowed to cool, when the 
strength which was obtained on parts influenced by the heat became a 
standard of comparison for experiments at more elevated temperatures. A 
mean of thirty-five comparisons, conducted in the manner just described, 
afforded a standard 16.2 per cent, greater than the ordinary strength of the 
metal; but the standard most relied on for furnishing the basis of calcula¬ 
tions, and for determining a law of diminution of tenacity, was derived 
from the five varieties of iron, manufactured by the Salisbury Iron Com¬ 
pany, which, being of a tolerably uniform texture, were considered rather 
more suitable than others for supplying the ground work of a law for cal¬ 
culating the effect of temperature on this metal generally. An examination 
of the trials on those bars will be found to furnish a standard of maximum 
tenacity 15.17 per cent, greater than their mean strength when tried cold. 
When, however, an unexceptionable standard was given by any bar after 
trial at 572° and subsequent cooling off, its own standard for increased 
strength was used in computing the true effect of heat at other high tem¬ 
peratures. 

Thus, at a temperature of 1317°, the bar No. 226, which had possessed, 
when cold, a strength of 54758 lbs., gave a remaining strength of only 
18913 lbs. Now, 54758 lbs. increased 15.17 of itself, gives 63065, 
and from this deducting 18913 we have 44152 lbs. for the diminution of 
its absolute tenacity by the temperature just mentioned, or .7001 of the 
maximum strength. 

On the same bar, (No. 226,) were made at different points, two other 
experiments with the same weight each time in the scale. 

The first of these sections gave way when the temperature had reached 
1237°. The strength per square inch given in this case was 21298, and 
comparing this with the maximum strength, 63065, we obtain 41767 as the 
diminution, equal to .6622 of that maximum. 

The second trial on a larger area of section required a higher tempe¬ 
rature to cause the fracture to take place under the given weight, viz : 
1245°, giving at this temperature a tenacity of 20703 lbs., and by the 
same computation showing a diminution from the maximum 63065 of .6715. 
Both of these trials having been made with the precaution of raising and 
lowering the suspended furnace, to regulate the heat, it is believed that no 
essential error in regard to temperature can have existed. The first was 
conjectured to be, if anything, a trifle in excess. 

If we take the mean of these two results, viz. .6668 for the diminution of 
tenacity at 1241° the mean temperature, it cannot vary far from the true 


214 


effect. On bar 227 an experiment was made at 1187°, giving a tenacity 
of 21913 lbs. per square inch. Within two and a half inches of the same 
point a cold fracture gave a strength of 52186 lbs., from which the calcu¬ 
lated maximum is 60102, and the diminution is 60102—21913, or 38189; 
which is .6352 of the same maximum tenacity. 

On No. 229 was made an experiment at 1159°, which exhibited a tena¬ 
city of 25620 lbs. Three experiments on the same bar when cold, gave a 
mean strength of 55774 lbs. Hence 55774X.1517=8460; and (55774 
+8460)—25620=38614, which is .6011 of the maximum tenacity. 

On No. 227 we have an experiment at 1155°, giving a tenacity of 21967, 
and the four cold experiments nearest to the same point give a mean of 
47749, from which we obtain the maximum 54992, and the diminution = 
.6000. 

On No. 226 was made an experiment at 1142°, but as the iron at the part 
in which the fracture took place was defective from flaws, and had probably 
been impaired by the previous straining of the bar, it was not considered 
necessary to attempt to reduce its apparent tenacity to the standard, being 
entirely anomalous. 

At 1111° the bar No. 227 had a strength of 27602, and another trial on 
the same at 1097°, 27602. 

The weight in the scale was the same in both cases, and the temperatures 
would probably have been the same, had not the standard piece in the latter 
case accidentally risen above the melted lead a short distance just before the 
fracture. Taking the mean of these two results 27603, for the strength at 
1111°, and the mean of six trials on this bar near the two points where 
these fractures occurred, viz: 53426, we obtain the maximum tenacity at 
those points 61531, and the diminution by heat .5614. 

On bar 152 an experiment at 1037° gave a tenacity of 37764, and on No. 
214 an experiment at 1022° gave 37410. The mean cold strength of these 
two bars was 59105, from which we deduce the maximum 68071; and the 
diminution for the mean temperature 1030°, equal to .4478 of the maximum. 

At 947° an experiment on bar No. 232 gave a strength of 42401, the 
mean of the two experiments subsequently made nearest to this point gives 
the experimental maximum strength 66193 from which the diminution 
is .3593. 

At 932° bar No. 214 had a tenacity of 45531, while its cold strength 
was 59319, and its maximum 68202, hence the diminution is .3324. 

An experiment was made on bar 149 at a temperature marked 825°, but 
as the furnace was not lowered during the performance of it, and as the 
time during which the bar continued to stretch after the strength had been 
fairly overcome, was considerable, the temperature is in all probability too 
high; and the experiment is not considered comparable with the rest of the 
series. 

In bar No. 214, at the temperature of 824°, the remaining strength was 
55892, the original strength, 60850, and the maximum by calculation, 
70080, whence the diminution is .2010. 

On bar 149 was an experiment at 770°, giving a tenacity of 54781; while 
the original strength was 56825, and the diminution from the calculated 
maximum .1627. 

On No. 16 we find an experiment at 766°, giving 54819. Two subse¬ 
quent experiments yielded maxima, the mean of which is 65176, whence 
the diminution is .1586. 


215 


In bar No. 150, a temperature of 734°, left a strength of 57903. The 
first experiment on the bar afforded 59397, from which we calculate the 
maximum 68407, which proves the diminution at this temperature to be 
.1535. 

On No. 14 we obtained a strength of 53378, at 732°, and the mean of 
three experimental maxima, is 62736, hence the diminution by heat is .1491. 

On No. 152 we had at 722° a tenacity of 54442, and three experiments 
gave a cold strength of 55990, from which a calculated maximum of 64483 
is obtained, and consequently a diminution of .1557. But an experimental 
maximum of 62709 was obtained on this bar, which on account of the re¬ 
moteness of the point where it occurred, from the point on which the hot 
fracture was made, is believed to be rather too low. Calculating, how¬ 
ever, from this maximum, we find the diminution .1316. 

If we take the mean of the two results, .1557 and .1316, we have the pro¬ 
bable diminution from the true maximum, .1436. 

On No. 150 we find an experiment at 662°, giving a tenacity of 58182. 
On the same bar an experimental maximum was found of 65785, from 
which we get the diminution equal to .1155. 

On No. 16 was made a trial at 636°, yielding a result of 50039, a result 
far lower than that given afterwards on the same bar at 766°; we are there¬ 
fore compelled to believe that this experiment was made on a defective part 
of the bar. 

On No. 219 A, was a trial at 630°, which exhibited a tenacity of 60010. 
An experiment subsequently made within If inches of the same point, gave 
a tenacity of 67033, and consequently the diminution is .1047. 

On No. 90 an experiment at 600° gave a tenacity of 56938, and three 
experiments on the same bar, when cold, gave a mean of 54715, from which 
the calculated maximum is 63015, and the diminution .0964. 

On the same bar (No. 90,) another trial took place at 596°, giving a 
strength of 57682 lbs., and if we assume the original strength of this sec¬ 
tion equal to that given by the third experiment on the same bar, 55037, 
we shall have the maximum by calculation 63386, and the diminution .0899. 

By a mean of 5 sets of experimental maxima derived from 65 trials on the 
5 varieties of Salisbury iron we have a standard of 66146. The six trials at 
the mean temperature of 570° referred to in our remarks in Table LXXIX. of 
the effect of employing different kinds of pig-metal, show that at a mean tem¬ 
perature of 570° those trials gave a strength of 60398 lbs., whence the di¬ 
minution is .0869. 

Of 224 B, at 520° the tenacity was 58451. On the same bar, four cold 
experiments gave a mean strength of 54934, which by calculation gives a 
maximum of 63267 and a consequent diminution of .0761. 

On a survey of the preceding discussions it will be seen that in de¬ 
termining the maximum belonging to each point of fracture, it has been ne¬ 
cessary to resort sometimes to experimental, and sometimes to calculated 
results, but that in several cases the two operate as checks upon each other. 

On attempting to extend the principle to trials made below the tempera¬ 
tures already cited, we are liable to encounter an ambiguity in the results, 
owing to the fact that the maximum tenacity is not generally to be obtained 
without having carried the previous temperatures to about 550° or 600°, 
and the tension to nearly or quite that of the original strength of the metal 
when cold. 


216 


In projecting into a curve as in Plate X. the data furnished by the ex¬ 
periments above described, and of which a synopsis is given in the follow¬ 
ing table, it becomes at once apparent that what was conjectured with 
respect to copper, in regard to a point of inflection, is here presented in a 
manner to admit of no uncertainty. Indeed it could hardly be otherwise, 
when we consider that the melting point of wrought iron, at which all 
tenacity must be overcome, is doubtless situated above 3000° ; and by the ex¬ 
periments of Clement and Desormes, is as high as 3945°. Now it appears 
that at a temperature no higher than about 1050° one-half of the strength 
is destroyed ; at 1240°, two-thirds ; and at 1317°, seven-tenths of the maxi¬ 
mum tenacity is overcome. 

The following table exhibits the observed temperatures, and correspond¬ 
ing tenacity of the metal with the calculated, or experimental maximum of 
strength,—the ratio of the observed diminution to the maximum tenacity, 
and the irregularity of the metal in parts of the original strength at ordi¬ 
nary temperatures. 

TABLE XC. 


No. of the comparison. 

Marks of the bar. 

Temperature observ¬ 
ed. 

Tenacity obse rved. 

Maximum tenacity at 
the point of fracture. 

Manner in which the 
maximum was obtain¬ 
ed. 

Diminution by heat 
in parts of the maxi¬ 
mum tenacity. 

Irregularity of the 
metal in parts of the 
original strength. 

1 

224 B. 

520° 

58451 

63275 

Experiment. 

.0738 

.0992 

2 

Salisb. iron. 

570 

60398 

60398 

do. 

.0869 

.1125 

3 

90 

596 

57682 

57682 

Calculation. 

.0899 

.2401 

4 

90 

600 

56938 

63086 

do. 

.0964 

.2401 

5 

219 A. 

630 

60010 

67033 

Experiment. 

.1047 

.1440 

6 

150 . 

662 

58182 

65785 

do. 

.1155 

.0644 

7 

152 

722 

54442 

64483 

Calculation. 

.1436 

.0507 

8 

14 

732 

53378 

62736 

Experiment. 

.1491 

.1310 

9 

150 

734 

57903 

68407 

Calculation. 

.1535 

.0644 

10 

16 

766 

54819 

65176 

Experiment. 

.1589 

.1563 

11 

149 

770 

54781 

65445 

Calculation. 

.1627 

.0234 

12 

214 

824 

55892 

70080 

do. 

.2010 

.0413 

12 

214 

932 

45531 

68202 

do. 

.3324 

.0413 

14 

232 

947 

42401 

66193 

Experiment. 

.3593 

.0446 

15 

C2i4? 

? 152S 

1030 

57587 

68071 

Calculation. 

.4478 

.0460 

16 

227 

1111 

27603 

61531 

do. 

.5514 

.0330 

17 

227 

1155 

21967 

54992 

do. 

.6000 

.0330 

18^ 

229 

1159 

25620 

64234 

do. 

.6011 

.1102 

19 

227 

1187 

21913 

60102 

do. 

.6352 

.0330 

20 

226 

1237 

21298 

63065 

do. 

.6622 

.1147 

21 

226 

1245 

20703 

63065 

do. 

.6715 

.1147 

22 

226 

1317 

18913 

63065 

do. 

.7001 

.1147 




















217 


From the eighth column of the preceding table it appears that of these 15 
different specimens of iron, the mean irregularity of structure is 10 per 
cent, of the mean strength when tried cold. 

For the purpose of ascertaining, approximately, the law of decrease in 
strength by temperature, an investigation was made similar to that adopted 
for copper, embracing, however, only 12 of the points contained in the 
preceding table. 

As some of the experiments which furnished the standards of comparison 
for strength at ordinary temperatures, were made at 80°, and as at that 
point small variations in respect to heat appear to affect but very slightly 
the tenacity of iron, it was conceived that for practical purposes at least, 
the calculations might be commenced from that point. 

Eighty degrees are therefore deducted from each temperature in the fol¬ 
lowing table, and the remainders used, instead of the numbers com¬ 
mencing from the 0 of our scale. It will be found that with the exception 
of a slight anomaly between 520° and 570°, amounting to —.08, the num¬ 
bers expressing the ratio between the elevations of temperature, and the 
diminutions of tenacity, constantly increase until we reach 932°, at which 
it is 2.97, and that from this point the ratio of diminution decreases to the 
limits of our range of trials, 1317°, where it is 2,14. It will also be ob¬ 
served, that the diminution of tenacity at 932°, where the law changes from 
an increasing to a decreasing rate of diminution, is almost precisely one- 
third of the total, or maximum strength, of the iron at ordinary tem¬ 
peratures. 

At this point it will be seen, the curve traced in the figure, Plate X., 
undergoes an inflection, and in all probability continues in the same general 
direction to the fusing point. 

TABLE XCI. 


c 

o 

tn 

* r* 
a 

Ch 

/— 

3 

a 

a> 

•-* 

o 

6 

£ 

Observed tempera¬ 
tures. 

Observed tempera¬ 
tures —80°. 

Observed diminution 
of tenacity. 

Power of the tem¬ 
perature which repre¬ 
sents the diminution of 
tenacity at each point. 

REMARKS. 

i 

520° 

440° 

.0738 

2.25 


2 

570 

490 

.0869 

2.17 


3 

596 

516 

.0899 

2.38 


4 

662 

582 

.1155 

2.67 


5 

770 

690 

.1627 

2.85 


6 

824 

744 

.2010 

2.94 


7 

932 

852 

.3324 

2.97 

Point of inflection near this temperature. 

8 

1030 

950 

.4478 

2.92 


9 

1111 

1031 

.5514 

2.63 


10 

1155 

1075 

.6000 

2.60 


11 

1237 

1157 

.6622 

2.41 


12 

1317 

1237 

.7001 

2.14 





Mean 

2.58 

• 















218 


From the above table it appears that the ratio of diminution furnished by 
a comparison of some of the lower temperatures with all those above them 
is higher than the duplicate. The same inference is derived from a compa¬ 
rison of the higher members of the series with all those below them. 

At 932° it will be seen that a comparison with all those both above and below 
that temperature, gives a rate very nearly approaching to the cube. The 
particular comparison between 824° and 932° gives a rate higher than the 
4th power, viz. 4.08. 

Hence though the diversity of the metals operated on, is such as not 
readily to furnish the precise mathematical law, it is still abundantly appa¬ 
rent that this law must be different from that which is indicated by any 
one of the family of parabolas.* 

But for practical purposes the table indicates, by the mean of all the rates, 
that a rule may be followed, not widely different from what is represented 
by saying that the thirteenth power of the temperature above 80° is pro¬ 
portionate to the 5th power of the diminution from the maximum tenacity .t 

Plate X. exhibits at .1517, in the line of observed diminution, the com¬ 
mencement of a branch of the curve descending to the right, which indicates 
the progressive effects of temperature, increasing, as it rises, the tenacity of 
iron until a certain point is reached, when the weakening influence begins to be 
felt. The other branch of the curve, or that which takes its rise from the 
origin of the abscissas, forms, with the first, a cusp of peculiar character at a 
point c, which, however, the experiments are not sufficiently numerous in 
this part of the scale to determine exactly in respect to position. 

From the preceding discussion Table LXXXIX. will be sufficiently in¬ 
telligible without further comment. 

Elasticity of Iron. 

In describing the method of determining the elasticity of the machine for 
tenacities, we have given in effect a detail of the processes also pursued 
with the bars of iron generally. 

The strong bar then interposed between the heads, b', b ", (Plate I.) was, 
however, now replaced by the specimen under trial, and as the machine 
was capable of overcoming the total strength of each specimen, the tempo¬ 
rary elongations, as well before as after the bar had begun to be permanently 
extended, were easily deducible from the observed elasticity of the bar and 
of the machine together , corrected by deducting the already ascertained 
elasticity of the machine alone. 


* Represented by the well known general formula, y q —mx p . 
f It is evident from what has already been said, that if we would calculate the 
reduction from the ordinary strength of iron as it comes from the hammer or the 
rolls, we must first reduce it to the maximum, by adding to its observed strength 
at a known low temperature, 15.17 per cent, of itself. It is, moreover, apparent from 
the curve, as well as from the table, that if we conceive the ordinates (y) or incre¬ 
ments of temperature, and the abscissas ( x ) or decrements of tenacity to be drawn 
from any two points below 932°, the increase ( dx) of any abscissa, for the contem¬ 
poraneous increase ( dy ) of the corresponding ordinate, will observe an increasing 

rate; but above that point where also the differential co-efficient, is a maximum, 

dx 

and where the differential co-efficient of the second order ~==O t they observe a de¬ 
creasing rate and the concavity of the curve is accordingly directed towards the axis 
of the abscissas, in place of the convexity which had hitherto inclined in that direc¬ 
tion. 


1.0000 


.1001 

.0115 

•on?? 

.005? 

• 0011 
. 00 ( 0 ) 


.5514 


•4470 


. 44 ? 4 


.?010 



•ii. : 


7.1 r: 


flateX 



- s/ 

O/jxm'<</ Temperatures . 


4 LlflT 































































































































rison 
At 
that t 
parti* 
4th p 
He 
readi 
rent i 
one c 
Bu 
that i 
by ss 
porti 
PI 
menc 
the p 
iron i 
felt, 
origii 
point 
this f 
Fr 
tellig 


In 

tenac 
with 
Th 
howe 
was ( 
rary e 
exten 
Of th 
elasti 


* R( * 

tH 

reduct 
rolls, 
at a k 
the cu 
ments 
from ; 
poram 

rate,- l 
and w' 

creasii 
of the 




219 


By referring to a former part of this report (Table III.) there will 
he found a series of numbers corresponding to the several observed 
elasticities of the machine, used by the committee, and representing in 
inches the actual distances, or quantities of recoil after the strain had been 
removed. From those numbers may be taken out by inspection, the quan¬ 
tity of recoil for each trial in the following table, and comparing the results 
thus obtained with the total lengths of the bars, it will be seen by what part 
of its whole length, each was elongated and contracted at every trial. 

It will not fail to be remarked that in the more extended series of the 
table, those for example, in which 7 or 8 trials were made on the same bar, 
the maximum of elasticity was often found within a comparatively small 
number of pounds of the breaking weight , and that it was seldom so low as 
two-thirds of that weight. This is at variance with the supposition that the 
elasticity of a bar is destroyed or much diminished at the moment it has 
begun to be permanently elongated. 

Second method of observing elasticities. 

Another method of approximately determining the elasticity of iron as 
indicated when subjected to different strains, was to measure directly on 
the specimen under trial the distance between two points, taken as remote 
from each other as possible, both when under strain and when that strain 
was removed. 

Thus bar No. 49 having been permanently elongated -yL of an inch, in 
20-—, under a weight of 273 pounds in the scale, gave a recoil of .05 of 
an inch. Afterwards with a weight of 301 lbs., and when a permanent 
elongation of .58 inch, in the same original length had taken place, the 
recoil amounted to -g-i-g. of the total length. After that trial 15 pounds in 
addition were required to break the bar. 

On bar 226 the first permanent elongation was found under a weight of 
245 pounds. Under a weight of 280 pounds the elongation in 24 inches 
was .86 inch, and when relieved it was .82, giving a recoil of .04 in 24 
inches,= 

After this last trial 35 pounds additional weight were required to produce 
the fracture. 

On bar 228, we find that the first elongation was taken under a weight 
of 232 pounds. With 238 pounds it had become .146 inch on a length of 
24; but when relieved the recoil was .046 inch, equal to T |- T of the length. 
Twenty-eight pounds were afterwards required to be added to break the bar. 

On bar 230 the elongation took place under 196 pounds. With 317 
pounds the recoil on a part originally 24 inches long was .05 inch, equal to 
of the whole original length, and 13 pounds more were required to 

produce the fracture. 

Experiments and remarks on this subject will be found in Tables 
XXXVII., XL., LV., LIX., &c. 


19 


220 


TABLE XCII .—Synopsis of the elasticity of 56 different bars of iron of given lengths, tinder cer¬ 
tain weights, and also the breaking weights of the same bars as found immediately subseyueiit to the 


No. of tht 
bar and di¬ 
rection of 
the slit. 

Length un¬ 
der trial. 

Weight in 
the scale. 

Elasticity 

observ. cor¬ 

rected for 
the machin. 

No. of the 

bar Jk direc. 

of the slit. 

Length un¬ 

der trial. 

Weight in 

the scale. 

Elasti. ob¬ 

served cor¬ 
rect. for the 
machine. 

No. ofbar 

Ik direction 

of the slit. 

Length un¬ 

der trial. 

► 

Weight in 

the scale. 

i 

Elastic, ob¬ 

served cor¬ 
rect. for the 
machine. 

2. 

23.55 

280 

15' 

39. C. 

23.5 

224 

20' 



452 

Broke. 

L’gth. 


336 

16 



314 

31 

58. C 

22.35 

448 

26' 



392 

19 



317 

Broke. 



479 

Broke. 



448 

25 

41. L. 

23.35 

224 

45 

58. C. 

20.7 

479 

57 



474 

21.5 



282 

27.5 



496 

Broke. 



479 

Broke. 

- 


292 

Broke. 

59. L. 

23.5 

112 

12.5 

4, L, 

13.2 

224 

35 

42. L. 

23.8 

224 

27 



168 

20 



336 

38 



336 

32 



224 

27 



448 

16 



399 

28.5 



242 

27 



460 

Broke. 



427 

31 



258 

Broke. 

8. 

21.2 

280 

20 



443 

Broke. 

61. L. 

23.6 

224 

40 

Cross. 


336 

22 

42. L. 

22.45 

399 

28.5 



280 

42 



392 

15 



427 

31 



326 

38 



430 

15 



452 

Broke. 



332 

36 



443 

Broke. 

42. L. 

18.8 

399 

28.5 



336 

Broke. 

17. Cr. 

23.9 

259 

23 



462 

22 

68. L. 

24. 

224 

32 



280 

22 



462 

Broke. 



336 

31 



294 

14 

44. L. 

23.7 

224 

25 



392 

28 



326 

17.5 



336 

25 



414 

30 



336 

21 



448 

23 



441 

32 



350 

24 



476 

36 



450 

Broke. 



364 

31.5 



496 

34 

68. L. 

20.8 

224 

32 



371 

27 



503 

Broke. 



448 

20 



374 

Broke. 

46. L. 

24.4 

224 

29 



455 

Broke. 

18. Cr. 

Unc. 

392 

32 



280 

29 

70. L. 

24.2 

112 

19.5 



403 

37.5 



297 

28.5 



224 

16 



412 

39 



314 

Broke. 



280 

19 



415 

26 

48. L. 

24.5 

224 

16 



336 

23 



415 

Broke. 



336 

18 



364 

26 

21. L. 

17.4 

280 

25 



425 

21.5 



377 

Broke. 



321 

26.5 



444 

30 

64. C. 

24.2 

112 

38 



336 

28 



464 

27 



224 

55 



356 

Broke. 



478 

31 



280 

51.5 

23. L. 

24.3 

280 

21 



487 

28 



301 

52.5 



364 

31 



503 

Broke. 



329 

46 



393 

Broke. 

51.C. 

24. 

224 

53 



335 

Broke. 

23. L. 

21.1 

280 

29 



336 

53 

65. C. 

24.25 

224 

19 



364 

22 



448 

27 



280 

18 



413 

57 



464 

32 



336 

27 



426 

Broke. 



472 

Broke. 



369 

Broke. 

25. L. 

24.1 

224 

39 

53. C. 

24. 

224 

37 

71.C. 

24.1 

224 

20 



361 

28.5 



336 

36 



336 

27 



370 

Broke. 



448 

21 



357 

Broke. 

27. L. 

24.2 

224 

35 



464 

22 

71.C. 

23.1 

336 

28 



336 

38 



478 

Broke. 



392 

26 



392 

53 

53. 

21. 

494 

25 



414 

Broke. 



403 

Broke. 



500 

Broke. 

73. C. 

23.95 

112 

5.5 

32. Cr. 

23. 

112 

10.5 

56. C. 

23.7 

224 

07 



224 

11 



168 

10 



336 

07 



280 

18 



224 

12 



448 

21 



308 

19.5 



280 

13.5 



471 

Broke. 



322 

33 



336 

16 

56. C. 

20.3 

448 

25 



336 

24 



392 

17 



495 

Broke. 



342 

Broke. 



410 

Broke. 

58. C. 

23.7 

224 

49 

85. L. 

24.5 

112 

11.5 

37. L. 

22. 

112 

23 



336 

54 



224 

15 



162 

43 



392 

50 



336 : 

33 



171 

Broke. 



448 

44 



392 

38 




























































221 


[TABLE XCII. continued] time of taking the elasticity. The direction of the slitting is indicated 
by the letters in the left hand column. 


N o. of the 
bar and di¬ 
rection of 
the slit. 

Length un. 
der trial. 

Weight in 
the scale. 

Elastic, ob¬ 

served cor¬ 
rect. for the 
machine. 

No. of the 

bar and di¬ 

rection of 
the slit. 

Length un¬ 

der trial. 

Weight in 

the scale. 

Elastic, ob¬ 

served cor¬ 
rect. for the 
machine. 

No. of the 

bar and di¬ 

rection of 
the slit. 

Length 

under trial. 

Weight in 

the scale. 

Elastic, ob¬ 

served cor¬ 
rect. for the 
machine. 



420 

36' 

101. L. 

25.1 

224 

35' 



420 

51' 



448 

24 



336 

41 



438 

49 



462 

Broke. 



403 

Broke. 



448 

45 

85. L. 

22.1 

224 

15 

103. C. 

23.8 

224 

38 



462 

46.5 



336 

23 



280 

34 



468 

Broke. 



392 

24 



308 

43.5 

174. D. 

30.2 

219 

45.5 



462 

28 



321 

Broke. 



227 

50.5 



481 

Broke. 

103. C. 

9.6 

168 

7 



235 

Broke. 

87. L. 

24.5 

224 

21 



361 

Broke. 

174. D. 

27.7 

231 

65 



336 

16 

105. L. 

24.2 

224 

63 



235 

Broke. 



392 

25 



294 

64 

174. D. 

23.9 

231 

41 



441 

25 



320 

63 



245 

44 



464 

Broke. 



322 

Broke. 



246 

Broke. 

75. L. 

24.6 

257 

8 

130. C. 

16.6 

56 

8 

174. D. 

22.1 

245 

39 



262 

Broke. 



112 

8.5 



246 

Broke. 

75. L. 

21.4 

168 

10 



168 

9 

148. C. 

unc. 

212 

29 



267 

Broke. 



224 

11 



336 

33 

78. L. 

24.4 

112 

14.5 



280 

13.5 



392 

42 



224 

17.5 



336 

12 



448 

45 



280 

21 



436 

16 



463 

Broke. 



280 

Broke. 



466 

12 

148. C. 

20.6 

463 

37 

78. L. 

Unc. 

224 

54 



485 

16 



476 

Broke. 



293 

Broke. 



506 

24 

151.C. 

30.5 

224 

30 

83. C. 

24. 

224 

34 



529 

Broke. 



336 

33 



273 

Broke. 

137. Di- 

4. 

490 

44 



448 

40 

84. C. 

23.8 

168 

50 

agonal. 


498 

Broke. 



476 

Broke. 



224 

52 

142. L. 

30.4 

112 

8.5 

151.C. 

29.8 

476 

36 



275 

54 



224 

14 



489 

Broke. 



289 

Broke. 



280 

15 

167. C. 

30.4 

224 

38 

84. C. 

9. 

224 

33 



336 

27 



266 

36 



317 

24 



364 

26.5 



284 

42 



319 

Broke. 



380 

32 



292 

Broke. 

84. C. 

15.2 

280 

53 



398 

31.5 

167. C. 

19.33 

306 

29 



294 

Broke. 



415 

Broke. 



307 

Broke. 

91. C. 

24. 

112 

50.5 

143. L. 

30.6 

224 

30 

160. L. 

30.2 

224 

82 



224 

76 



280 

33 



245 

Broke. 



280 

60 



336 

48 

160. L. 

22.25 

252 

64 



347 

34 



370 

53 



257 

Broke. 



364 

20 



392 

52 

162. L. 

30.2 

168 

60 



392 

Broke. 



435 

44 



224 

65 

94. L. 

24.07 

224 

37 



440 

47 



252 

58 



280 

45 



440 

Broke. 



256 

Broke. 



336 

38 

143. L. 

29.3 

464 

41 

162. L. 

27.6 

262 

72 



392 

36 



478 

Broke. 



262 

Broke. 



448 

25 

154. D. 

30.4 

224 

30 

181. 


112 

20.5 



483 

25 



336 

30 

Steel 


224 

30 



511 

Broke. 



392 

38 

bar. 


336 

28 

95. C. 

24.1 

224 

34 



420 

42 



385 

36.5 



336 

26 



427 

Broke. 



406 

40.5 



382 

Broke. 

154. D. 

23.08 

392 

21 



415 

39.5 

99. C. 

24.3 

224 

20 



438 

Broke. 



422 

36.5 



336 

36 

157. D. 

30.35 

224 

27 



429 

37.5 



378 

42 



336 

50 



441 

Broke. 



378 

Broke. 



392 

50 
























































222 


TABLE XCIII, 


Comparative view exhibiting the areas of section at the points of 
fracture in 151 experiments on 67 different specimens of iron , embracing 


No. nf the comparison. 

Number of the specimen refer¬ 
red to. 

No. of experiments on the respec¬ 
tive specimens. 

Area, after fracture, of strips 
cut lengthwise, compared with 
their original area as unity. 

Arta of section of fracture of 
specimens cut transversely, their 
original area being .1. 

Mean area of length strips in 
each kind of iron. 

Mean area of cross strips in each 
kind of iron. 

Number of the comparison. 

Number of the specimen. 

Number of experiments on the 

respective specimens. 

Area after fracture of strips cut 

lengthwise, compared with their 

original area as unity. 

Area afttr fracture of specimens 

cut transversely. 

Area after fracture of specimens 

cut diagonally. 

1 

2 

2 

.887 




34 

71 

4 


.781 


2 

4 

2 

.829 




35 

73 

1 


.830 


3 

6 

2 


.904 



36 

85 

3 

.889 



4 

8 

1 


.895 

.858 

.899 

37 

87 

2 

.800 










38 

75 

1 

.869 



5 

9 

1 

.876 




39 

78 

1 

.840 



6 

11 

2 

.771 




40 

81 

1 


.978 


7 

21 

2 

.909 




41 

83 

3 


.901 


8 

23 

3 

.876 




42 

84 

3 


.859 


9 

13 

2 


.860 









10 

15 

1 


.867 



43 

94 

4 

.760 



11 

18 

1 


.964 

.858 

.897 

44 

95 

5 


.872 


12 

25 

6 

.824 




45 

99 

1 


.947 


13 

27 

1 

.936 




46 

103 

2 


.810 


14 

35 

1 

.909 




47 

107 

3 


.816 


15 

37 

1 

.949 




48 

101 

2 

.849 



16 

32 

1 


.840 



49 

105 

1 

.895 


• 

17 

39 

1 


.934 









18 

41 

1 


.927 

.904 

.900 

50 

125 

2 

.502 

.766 









51 

130 

1 



19 

42 

3 

.923 




52 

133 

5 


.587 


20 

43 

1 

.924 




53 

135 

5 



.512 

21 

44 

2 

.914 




54 

137 

3 



.544 

22 

56 

2 


.920 









23 

58 

4 


.883 

.920 

.901 

55 

142 

1 

.941 










56 

143 

3 

.780 



24 

46 

2 

.790 




57 

160 

5 

.772 



25 

48 

2 

.761 




58 

162 

2 

.735 



26 

51 

2 


.838 



59 

164 

5 

.457 



27 

53 

2 


.865 

.775 

.851 

60 

148 

2 


.885 









61 

151 

5 


. 84 7 


28 

59 

1 

.890 




62 

167 

2 


.729 


29 

61 

1 

.891 




63 

169 

6 


.835 


30 

64 

1 


.967 



64 

154 

3 



.877 

31 

65 

1 


.940 

.890 

.953 

65 

157 

1 



.842 

32 

68 

2 

.833 




66 

171 

1 



.412 

33 

70 

1 

.858 




67 

174 

4 



.805 





































































































223 


TABLE XCIII. 


11 kinds of metal, distinguishing those specimens which were cut length¬ 
wise Jr om those which were cut crosswise and diagonally from the sheet. 




3 

<m 


C3 

QJ 

U 

cz 


a • 

■ 


•84 5 


.849 


V 

V 

a* 


0) 
Of5 

3 


Cm 

O 


CS 

Z> 


33 . 

1/ CO 

Sg 


.805 


s 

1> 


Z 


a 

G 

o 

iuO 

as 

‘-5 

Cm 

O 

c3 

V 


cc 


.912 


.760 


.872 


.872 


,85/ 


.502 


.679 


.523 


.737 


.824 


859 


REMARKS. 


From this table it appears that the areas of fracture in strips 
cut across the direction of the rolling, are greater than in those cut 
longitudinally. The difference in this respect on the 12 dif¬ 
ferent kinds, averages 6 per cent, of the area of the fractures in 
the longitudinal strips,—a difference corresponding very nearly 
with the difference in strength of longitudinal and transverse 
strips as contained in Tables XCV. and XCVI. 

It also appears that of the 12 different sorts of iron compared, 
8 exhibit a diminution of area in the length strips, greater than 
in those cut across the direction of the rolling, and 4 show a 
small balance in the opposite direction. 

The mean difference of the 8 sets first mentioned, is .8G1— 
.778=. 083 of the original area, or .107 of .778, the remaining 
area in the case of the length strips. 

The mean of all the 67 comparisons in all directions exhibits 
the diminution of area from 1.000 to .835, or a “ constriction” 
of .165=1-6 the original size, and of course a correspondent 
increase of length at the parts in the immediate vicinity of the 
fractures. 


19 * 















































22 4 


Diminution of area at the moment of fracture. 

With a view to determine within certain limits the extensibility of iron 
when subjected to strain, and to compare the same in specimens cut across 
the sheet with that of longitudinal strips, a considerable number of measure¬ 
ments were taken at the sections of fracture after the experiment, and from 
these the above table of results is exhibited, indicating the mean result of 
the trials on each bar and the ratio of the remaining area to the original 
area taken as unity. 

In taking these measurements some little uncertainty is to be admitted, 
owing to the fracture taking occasionally a diagonal direction, but as the 
two fragments afforded the means of obtaining corrections, the error 
from this cause cannot have, at most, exceeded a few thousandths of 
an inch. 

By referring to the table of permanent elongations as taken on the whole 
bar, (Table XCIV.), it will be seen that the greatest extension observed on an 
entire bar, previous to the first fracture, was 3 inches in 24 or £ of the 
total length. This was on a bar reduced to a uniform size. But as no bar 
of iron, of any considerable length, is of uniform strength throughout, we 
are not to expect in any case an extension in length of the whole bar equal 
to the diminution of area at the point of fracture. 

One remark worthy of particular attention, in connection with our sub¬ 
ject, is, that at elevated temperatures, before the diminution of strength has 
begun to be felt, the diminution of area or constriction of iron is often much 
less, than when the trial is made on the cold metal. This is particularly 
exemplified in bar No. 164, in which two experiments at 577°, gave a 
tenacity 14 per cent, greater than five others, made at from 75° to 80°, while 
the constriction was less in the hot trials than in the cold, in the proportion 
of .338 to .447, or about one-third. In this and similar cases the fractures 
at high temperatures were observed to take place suddenly, and the surfaces 
of fracture to present appearances altogether different from those found in 
cases where the same bar was broken cold. This peculiarity consisted in 
a smooth section, directly across the breadth of the filed portion in which 
they took place, but uniformly inclined to the flat face of the bar, in an angle 
of about 45 degrees, and presenting therefore a bevel, like the cutting edge of 
a common mortising chisel. 

In a few instances, particularly in experiments on bars as they came from 
the shears, the fracture was compound, the strengths at two neighboring sec¬ 
tions being so exactly equal as to separate simultaneously, at the distance of 
half an inch or an inch from each other. 

Bars 228 and 230, the former of which was cut crosswise, and the latter 
lengthwise of the sheet, and both broken up at ordinary temperatures, indi¬ 
cated a marked difference in the nature of the surfaces of fracture. The 
former presents, in nearly all instances, irregular and jagged surfaces in¬ 
clining to compound fracture, or displays rough sections perpendicular both 
to the edges and faces of the bar. The latter is oblique and fibrous. 

The amount of constriction in strips cut across the direction of rolling 
is, on an average, about 6 per cent, less than in those cut longitudinally. 

A careful comparison of the breadths and thicknesses before and after 
fracture would show that the diminution in thickness follows a more rapid 
rate than that in breadth, whether the iron be hammered or rolled, and 
whether in the latter case, it be cut lengthwise or crosswise of the sheet. 

The amount of constriction observed, viz: 16£ per cent., is rather less 


225 


than that obtained by M. Martin,* who operated chiefly on rolled bars or 
bolts of considerable magnitude, and found on an average of 35 comparisons 
18 to P er cent * °f elongation. 

The above table will show that the difference in different kinds of 
metal in respect to the diminution of area of fracture is very marked, some¬ 
times exceeding 54 per cent, of the whole original area; while at others it 
scarcely exceeds 5 per cent. 

The difference in the extensibility of iron in the longitudinal and the 
transverse directions of the sheet is liable to manifest itself in practice, when 
a portion of a boiler becomes locally so overheated as to bulge out in a par¬ 
ticular spot. It will then be seen that an elongated protuberance is exhibited, 
having the greater axis in the direction across the sheet, and the less lying 
in the course of the rolling. 

The piece taken from an old boiler which had been burst in consequence 
of the gradual overheating of a portion over the fire where sediment had 
collected, and which will be referred to in another part of this report, ex¬ 
emplifies the kind of action above described. The extent of the swelling in 
the direction of the length of the sheet was 10 £ inches, which, measuring 
over the summit of the bulge, had become 12 ? inches; or the increase of 
distance over the surface of the metal was .167 of the original extent. In 
the transverse direction of the rolling, the original length of the swollen part 
was 2 O 3 inches, and the line applied over the summit measured 23 inches, 
or the increase in this direction was .122 of the original length. Hence the 
extensions of this specimen of iron in the two directions are to each other 
as 167 to 122. 

Some idea may be formed of the extent of constriction in breadth , both 
of iron and copper bars under various temperatures, by inspecting Plate II. 
m and m! are two portions of bar No. 164, Table XLVIII., which was pre¬ 
pared by filing notches on its sides. The portion m, of which the breadth 
before trial was .747 inch in the deepest part of the filed section and .132 
inch thick, was broken at a temperature of 576°. Strength, 66336 pounds 
per square inch. The breadth after fracture was .674 inch, and the 
thickness . 102 . The surface clean, smooth and bevelled in an angle of 
about 45°. The diminution of area is consequently .098604—.068781 = 
.029823 square inch, m' represents a portion broken in experiment 15 of 
the same table, at a temperature of 87.5°, giving a strength of 56503 pounds 
per square inch, and a section of fracture measuring .601 in breadth and .07 
in thickness;—whereas the original breadth had been .731 and thickness 
.138 ; so that the constriction was here .100878 —.042070==.058808 square 

Inch,_almost exactly double as much as when broken at 576°. Experiment 

17 on the same bar affords another illustration of the effect of a moderately 
elevated temperature in preventing constriction. 

The original breadth of the bar in which these notches were filed was 

1.117 inch. Hence the notches in m were each - 


1.117—.747 


2 


= .185 inch 


deep, and those in m! each about .193 inch, in both cases quite sufficient to 
preclude the supposition of any weakening effect of the shears, within the 
part left after filing. 

n and n' are portions of the bar of iron, No. 224 C, an account of which is 
given in Table LXXII. The breadth before trial of this bar, which was reduced 

* See Annales des Mines, 3d series, Vol. V. 1st pan. 



226 


to uniform size by filing, is indicated by the dotted lines outside of the plain 
ones, while the inside dotted lines mark the breadths after fracture. 
Both portions were broken at low temperatures, n' in experiment 5 of 
that table, at a temperature of 80°, exhibited a strength of 62472 pounds 
per square inch, a breadth of section=.572 inch, and a thickness of .159, 
consequently giving an area of section after fracture of .090948 square inch, 
whereas the area before trial was .182945, and the constriction .091967, a 
trifle more than 50 per cent, of the original section. The fracture on the 
portion n was made at the 8th experiment of the same table when the tem¬ 
perature was 71°, and within one inch of the point broken in the trial just 
referred to. But previously to this fracture, the specimen had been sub¬ 
mitted without access of air to a bright welding heat, so as perfectly to 
anneal the iron without oxidizing it. The strength was then found to be 
only 36052 pounds per square inch, reckoned on the original section at that 
part of the bar, the breadth being .457 inch, the thickness .118, and the area 
.053926; while the original breadth had been .757, original thickness, .24125, 
and area .182626, which had been reduced before the annealing to .150664. 
Hence the constriction after annealing was .182626—.053926=.128700, or 
70.4 per cent, of the original cross section of the bar. 

o and o’ represent specimens of copper bar, No. 7 table XXII., to which 
we have already referred in speaking of the extensibility of that metal. 

Forces producing permanent elongations of iron. 

In connexion with the subjects of tenacity and elasticity, it has generally 
been deemed important to pay some attention to the relation between the 
forces which will break, and those which will elongate the specimens to a 
sensible degree, rendering them incapable of returning to their original di¬ 
mensions. The committee have not been unmindful of this subject, and the 
following table will exhibit the most important of these observations, which 
have, during the course of our experiments, been made to bear directly on 
this point. An inspection will show that the first permanent elongation 
may take place under forces varying according to the character of the mate¬ 
rials. Those kinds which possess the greatest extensibility begin in general 
earliest to manifest this property, in yielding permanently to low degrees of 
force. This remark is exemplified by a comparison between Nos. 226 and 
219 A., the latter of which showed an extensibility before fracture of 2.5 
inches in 24, or about JL of its whole length, and began to extend with 41-f 
per cent, of the breaking weight, while the former was extended -fa of its 
length, or 1^ inch in 24, and required 76 per cent, of the breaking weight 
to cause the first elongation. The extremes lie between .416 and .872 of 
the ultimate strength; and the mean of 13 comparisons is .641, conforming 
nearly with the results obtained by former experimenters. 

The eighth and ninth columns of the following table show the total 
elongation at the moment of fracture. This must necessarily be different 
in different bars, as well on account of the diversity in their constitution, 
as of the unequal degrees of uniformity in size and structure in different 
parts of the same bar. 


227 

TABLE XCIV. 

Compar ative table exhibiting the amount and relations of the weights 
required to produce the first permanent elongation in different bars of 
ii on, and the weights required for the first fracture of each bar , also 
the amount of permanent elongation of the specimen , and the ratio 
winch that elongation bears to the entire length before trial . 


e 

c 

* 3 

A 

w 

U ~ 

• 

1> 

+■* CJ 

He 


0/ flU 

‘SoS 


'u 

as 

£ 

o 

u 

V 

w 

<*-. 

o 

c 

s? 

Mark of the bar 
fording’ the comp 
son. 

Original length of 
part measured. 

Strength in lbs. 
square inch, exhibi 
by the first fracture 

No. of pounds in 
scale at the first frai 

Wt. in the scale at 
permanent elongati* 

Ratio of the elongat 
to the breaking iveig 

Elongation in incl 
at the time of fractu 

Pt. by which the ori 
nal l’gth was increas 

REMARKS. 










r When strained with 273 lbs. and 
then relieved, the recoil of the part 
within the marks originally 20.3 in. 

1 

49 

20.3 

57565 

316 

245 

. 775 

1.42 

1 

1 4 

apart, was .05 of an inch ; with 301 
<( lbs. in the scale it was .06, and with 










306 lbs. it was .04. The mean of 










these 3 tiials of the recoil, shows 
that it amounted to of the origi- 

2 

149 

24. 

52778 

334 

224 

.670 



Inal length. 

3 

150 

24. 

59397 

346 

196 

.566 

1.5 

1 

1 6 


4 

191 

15. 

47991 

326 

210 

.644 

1.42 

1 

lT 


5 

219 A. 

220 B. 

24. 

52257 

267 

112 

.416 

2.5 

3. + 

* 

X 

"9'6 

r Under 289 lbs. the 24 inches had 

6 

24. 

58642 

336 

184 

.547 

1 

8 

< become 27, and the bar had ex- 

7 

223 A. 

24. 

43766 

269 

168 

.622 

i- H - 

1 

2 4 

C. tended very uniformly. 









C The first permanent elongation 

8 

223 B. 

22. 

41555 

262 



2.55 

1 

J of this bar was not observed, but 



^•6 

) under a weight of 245 lbs. in the 
Lscale the elongation was .7 inch. 







9 

226 

24. 

49053 

315 

240 

.761 

1.5 

1 

1 6 

r Under a weight of 238 lbs. in 


228 








the scale, the elongation in 24 
inches was .146 inch; but when 

10 

24. 

40643 

266 

232 

.872 

.697 



< relieved the recoil was .046, show¬ 
ing the permanent elongation to 
be.l inch, and the ratio of the re- 
j;oil to the total length 

229 

11 

12. 

46473 

301 

210 



12 

230 

26. 

49368 

330 

196 

.594 

2.36 

1 

1 1 


13 

231 

22. 

68513 

465 

308 

.662 




14 

232 

24. 

57039 

376 

196 

.508 







Mean of 13 

.641 







Maximum 

.872 







Minimum 

.416 



















































228 


It is not only desirable to mark the force which will produce the first 
permanent elongation of iron, but also to ascertain the successive elonga¬ 
tions under different weights, since in the case of the steam-boiler it may 
be necessary to know what degrees of distortion in its form would result 
from the various forces which might be applied to it. It is true that in pro¬ 
ducing these successive elongations time may enter as an element into the 
result; but the experiments of the committee on this subject, were gene¬ 
rally conducted with such deliberation as to preclude the supposition that a 
longer continuance would have materially altered the effects observed. In 
determining this question, recourse was had to two methods; first, that of 
direct measurement of the lengths after certain elongating forces had been 
applied, and secondly, that of gauging the cross sections at numerous 
equi-distant points along the bar, the results of which showed the irregu¬ 
larity of extension as well as its actual amount in the vicinity of each 
section so gauged. 

Table XLVIII. affords an example of the latter kind of trials, in which 
the bar was gauged each time, after eight different experiments. 

Tables XXXVIII., XXXIX., XLII., LXXXII., LXXXIII., LXXXIV. 
and LXXXVII., will also be found to contain accounts of similar mea¬ 
surements of cross sections. 

Experiments and observations on the progressive extensions in length 
of bars of iron, will be found in Tables XXXVII., XXXVIII., LXV., 
LXXXII. Sind LXXXIV. 

Strength of iron in different directions of the rolled sheet. 

In obtaining specimens for these experiments, care was generally taken to 
have them cut in different directions of the rolling, longitudinally and trans¬ 
versely, and in some cases diagonally , to that direction. The tables will 
be found to indicate the direction of slitting in each case, and the comparison 
contained in Tables XC V. and XCVI. is given to show what information the 
inquiry has elicited. 

The comparison is made principally on the minimum strength of 
each bar, being that which can alone be relied on in practice ; for if the 
strength of the weakest point in a boiler be overcome, it is obviously unim¬ 
portant to know that other parts had a greater strength. In one case, how¬ 
ever, two bars, one cut across the direction of rolling and the other longitu¬ 
dinally, were, after being reduced to uniform size, broken up cold, with 
a view to this question. The result shewed that the length-strip was 
Vcr P er cent * stronger than the one cut crosswise, considering the tenacity 
of the latter equal to 100. Of the other sets, embracing about 40 strips cut 
in each direction, it appears that some kinds of boiler iron manifest much 
greater inequality in the two directions than others. It is in certain cases 
not much over one per cent., and in others exceeds twenty, and as a mean 
of the whole series it may be stated to amount to six per cent, of the strength 
of the cross-cut bars. The number of trials on those cut diagonally is not 
perhaps sufficiently great to warrant a general deduction, but so far as they 
go, they certainly indicate that the strength in this direction is less than in 
either of the others. 

Had we compared the mean instead of the least strength of bars as given 
in the table, the result would not have differed materially in regard to the 
relative strength in the respective directions. 


229 


i 


For this purpose the boiler-iron manufactured by Messrs. E. H. & P. 
EUicott, which was tried in all three of the directions of the sheet, and by 
all the three modes of preparation of specimens, will be found to give the 
following results,—viz, 1. When tried at original sections , seven experi¬ 
ments on length-sheet specimens gave a mean strength of 55285 lbs. per 
square inch, the lowest being 44399, and the highest 59307. Fourteen 
experiments on cross-sheet specimens gave a mean of 53896 lbs., the lowest 
result being 50212, the highest 58839; and six experiments on strips cut 
diagonally from the sheet, exhibited a strength of 53850 lbs., of which the 
lowest was 51134, and the highest 58773. 

2. When tried by filing notches on the edges of the strips to remove all 
weakening effect of the shears, the length-sheet bars gave, at fourteen frac¬ 
tures, a mean strength of 63946, varying between 56346 and 78000 lbs. 
per square inch. The cross-sheet specimens tried after this mode of pre¬ 
paration, exhibited, at three trials, a mean strength of 60236 lbs., varying 
between 55222 and 65143; and the diagonal strips, at four trials, gave a 
mean result of 53925, the greatest difference being between 51428 and 56632. 

3. Of strips reduced to uniform size by filing, four comparable experi¬ 
ments on those cut lengthwise of the sheet, gave a mean strength of 63947, 
of which the highest was 67378 and the lowest 60594. 

Cross-sheet specimens tried after the same preparation, exhibited, at 
thirty-three fractures, a mean of 50176, of which the highest was 65785 
and the lowest 52778. No bar cut. diagonally was reduced to uniform size. 

From the foregoing statements it appears that by filing in notches and filing 
to uniformity,we obtained results 63946 and 63947 for the strength of strips 
cut lengthwise, differing from each other but a single pound to the square 
inch, and that by these two modes of preparation the cross-sheet specimens 
gave respectively 60236 and 60176, diff ering by only 60 lbs.to the square inch. 
This seems to prove that by both methods of preparing the specimens the 
accidental weakening effect of slitting had been removed by separating all 
that portion of the metal on which it had been exerted. Hence we may 
infer that the differences between length-sheet and cross-sheet specimens 
are really and truly ascribable to a difference of texture in the two direc¬ 
tions, which will be seen to amount, in the case of filing in notches, to 6.15 
per cent., and in that of filing to uniformity, to 6.26 per cent, of the strength 
of the cross-sheet specimens. 

The single exception to the law that the greater strength is given in the 
longitudinal direction of the rolling, will be found explained in the remark 
appended to table NCV. 



TABLE XCV 


Comparative view of the strength of specimens of ten different 
sorts of boiler and one of bar iron, in the longitudinal , transverse , 
and diagonal direction of the rolling , as deduced from the least 


No. of the specimen 
referred to. 

Strength in the longi¬ 
tudinal direction. 

Strength in the trans¬ 
verse direction. 

Specific gravity. 

2 

58977 


7.7169 

3 

53828 


7.7169 

4 

4714 


7.7169 

6 


52280 

7.7169 

8 


50103 

7.7169 

Mil. 

53324| 51191 

1 

9 

57952 


7.7874 

10 

64133 


7.7874 

11 

42000 


7.7874 

13 


50488 

7.7874 

14 


52542 

7.7874 

15 


50166 

7.7874 

16 


50039 

7.7874 

17 


44249 

7.7700 

18 


50218 

7.7700 

19 


49125 

7.7764 

21 

38618 


7.7700 

22 

47491 


7.7700 

23 

42798 


7.7700 

Mn. 

48832 

49546 


25 

43921 


7.7640 

27 

55636 


7.7640 

30 


44703 

7.7640 

32 


52197 

7.7640 

35 

43237 


7.7954 

37 

46155, 


7.7954 

, 39 


40595 

7.7954 

41 


37713 

7.7954 

Mn. 

47237| 

43802 


42 

51653 

Puddled. 

7.6820 

43 

44102 

do. 

7.6820 

44 

53836 

do. 

7.6820 

46 

59262 

H’d pla. 

7.6785 

48 

59418 

do. 

7.6785 

49 

57565 

do. 

7.6785 

51 

H’cl pi 

59656 

7.7567 


No. of the specimen 
referred to. 

Strength in the longi¬ 

tudinal direction. 

Strength in the trans¬ 

verse direction. 

Specific gravity. 

No. of the specimen 

referred to. 

Strength in the longi¬ 

tudinal direction. 

53 

56 

58 

59 

60 

H’d pla. 
Puddled, 
do. 

48308 

58684 

52869 

57612 

Puddled. 

do. 

57929 

47638 

H’d pla. 
do. 
do. 

56062 

57926 

50570 

Puddled. 

do. 

do. 

do. 

45392 
51255 
H’d pla. 
do. 

54634 

52657 

49351 

7.7567 

7.6511 

7.6511 

7.6013 

7.6013 

7.6013 

7.6013 

7.6511 

7.6511 

7.7900 

7.7900 

7.7900 

7.7900 

7.7910 

125 

130 

133 

135 

137 

57182 

Tilted. 

do. 

do. 

do. 

- 61 

Mn. 

57182 

64 

65 
68 

70 

71 

73 

74 

142 

143 
146 

148 

149 

150 

151 

152 

44399 

53135 

60594 

Mn. 

54074 

53049 


154 


75 

60408 


7.7580 

157 


78 

41734 


7.7580 

160 


81 


42903 

7.7580 

162 


83 


42162 

7.7580 

164 

56346 

84 


42696 

7.7580 

167 

56682 

85 

48694 


7.7580 

169 

54361 

86 

58969 


7.7580 

171 


87 

50249 


7.7580 

174 


88 

49508 


7.7922 

Mn. 

54253 

90 


4^060 

7 7580 



91 

i 

42365 

7.7580 

200 

201 


Mn. 

51760 | 

43037 

1 

206 

44149 

94 


53811 


207 

48120 

95 


45471 


208 

52175 

QQ 


A O £ A Q 




y y 

101 

49258 



Mn. 

48148 

103 


41319 


226 


105 


44591 


227 


107 


55461 


228 

oon 


Mn. 

49258 | 

48366 | 








230 

49368 





Mn. 

49368 



















































































231 


TABLE XCV. 

^ strength of each specimen, and the average minimum of each 
\ so ^t of iron , in each direction in which it was tried, together 
(.with the specific gravity of the several bars. 


UO 

i 

O 


re 

to 

re 


V 

-5 

V 

• 

■£ a 
a.2 

mm 

w 

p a 

re 


•A 

tog 

C u 

tC 


u 

<u 


60 15 

ud 

> 



Tilted. 



57789 

53176 

47738 

50358 


55882 

49048 

1 



7.7390 

52468 

52228 


7.7774 

56869 

53811 


7.7774 

56073 

51134 

52102 

7.7774 x 

53862 

50212 

55612 

51425 


53646 

52568 


40163 

46970 




43566 | 


49053 


7.7428 

53699 


7.6675 

40643 


7.6675 

46473 


7.7428 



7.6675 


REMARKS. 


The only set of these experiments in which the 
bars cut crosswise of the sheet appear to be stronger 
than those cut lengthwise, is that from 9 to 23,—of 
which 3 of the length strips were from the same 
specimen,—a specimen in which a large flaky portion 
was developed by the trial. This set is therefore not 
to be taken into the account in computing the relative 
strength of the two classes of bars. 

The specimens from 42 to 74, were partly puddled 
iron, and partly Juniata blooms, hammered and rolled 
into plate. The length and the cross-sheet speci¬ 
mens of these two kinds must be compared separately 
as shown in the table (XCVI.) of general results. 

All the experiments on No. 228 (cross,) and 230 
(length,) were made at ordinary temperatures with a 
view to this comparison. 


47467 | 


20 


































232 

TABLE XCVI. 

General results of the several comparisons between bars cut in 
the different directions. 


Sets of specimens com¬ 
pared. 

No. of experiments 
on longitudinal bars. 

Strength of specimens 
cut lengthwise. 

No. of experiments on 

transverse bars. 

Strength of specimens 

cut crosswise. 

No. of experiments on 

diagonal bars. 

Strength of bars cut 

diagonally. 

Excess of longitudi¬ 

nal, over transverse 
specimens. 

Excess compared with 

the whole strength of the 

cross cut bars as unity. 

2— 8 

3 

53324 

2 

51191 



2133 

.0416 

25— 41 

4 

47237 

4 

43802 



3435 

.0784 

75— 91 

6 

51760 

5 

43037 



8723 

.2026 

94—107 

1 

49258 

6 

48366 



892 

.0184 

125—137 

1 

57182 

2 

55482 

2 

49048 

1700 

.0306 

142—174 

6 

54253 

7 

53646 

4 

52568 

607 

.0113 

200—208 

3 

48148 

2 

43566 



4582 

.1051 

226—230 

1 

49368 

4 

47467 



1901 

.0421 

Ham’d plate. 

5 

56366 

5 

54872 



1894 

.0347 

Puddled iron. 

7 

52437 

4 

51411 



1026 

.0200 

Mean of 

37 

51933 

41 

49247 

6 

50808 

2689 

.0585 

Mn. of ex. on 









228—230 

13 

54022 

13 

50433 



3589 

.0711 


From the above comparison of nearly eighty specimens, from ten differ¬ 
ent sorts of iron, it appears that the average minimum strength of iron in 
the direction in which it is rolled, is very nearly 6 per cent, greater than 
that in the transverse direction. 

Specific gravity of Boiler-Iron. 

Table XCY. contains in addition to a view of the relative tenacities of 
strips cut lengthwise and crosswise of the boiler plate, a column exhibiting 
the specific gravities of the several kinds of iron there compared. In most 
cases, these were obtained by cutting from the same sheet which furnished 
the strips, and in a contiguous part, a small sample, expressly intended for a 
trial of its density. Several bars will consequently be found to have the 
same specific gravity assigned to them. But we have still no less than 
nineteen different experiments from which to deduce the general result. 
From these it appears that the highest density was 7.7922, the lowest 
7.6013, and the mean 7.7344; also, that the difference .1909, between the 
maximum and the minimum is T part of the mean density, which may 
accordingly be taken as the limit of variations in this particular. 

Seventeen different trials of specific gravity on bar iron gave a mean of 
7.7254, and the greatest difference between any two results was 7.8319— 
7.4587=.3832, or ^A_ of the mean density. 

Effect of repeated Piling on the tenacity of Plate-Iron. 

The effect of repetitions of the process of piling and welding, whether of 
puddled iron or blooms, is exhibited in table XCVII., in which are contained 
the results of trials on three specimens of iron, furnished by an establish¬ 
ment in Centre County, Pennsylvania, a region known to afford an ore of 
superior quality, and which has long supplied wrought iron, inferior to few 
other kinds of the article known in the American market. 
































233 


TABLE XCVII. 

Experiments on bars A T o. 242,243 and 244. Manufactured by Messrs. 
Valentine fy Thomas, near Bellefonte, Centre County, Pa., from metal ob¬ 
tained from pipe ore, found 15 miles north of that place. No. 242 from 
“refinery bloom ”, extended into bars three inches wide by one inch thick , 
piled four high and twice welded. No. 243 also from “refinery bloom,” 
twice welded. No. 244 manufactured from puddled iron, rolled at the first 
operation into 31 by 1 inch, then cut up and piled 4 tiers high, welded 
again and extended into a billet, then a second welding and rolling into 
the shape in which it was received. 



£ 

<v 


• 

2 

13 

• h 
i- 

i 

V 

A 

c 

«-> 

X 



u 

P, 


u 

CS 

a 

A 

s 

u 

4* 

X 

0) 

DATE. 

w 

<2 

s 

A 

u 

<2 
a j 

A 

C/J 

G 

.2 

o 

0/ 

V) 

m* 

UJ 

3 

bp 

g weight 

• 

g 

’3 

u 

<s> 

0) 

Oft 

C 

s 

o 

p. 

.S j 

REMARKS. 

O 

o 

£ 

.£ 

w 

O 

o 

£ 

. 

JZ 

w 

cl 

0) 

M 

V 

a 

V 

• *4 

A 

H 

Area ol 
fore trial. 

Breakn 
the scale. 

Breakin 

leverage. 

Friction 

► 

■*-> 

o 

& 

w 

Strength 
squareinc 




1835. 

Nov. 









All the bars had been 
reduced when received 

242 

l 

.753 

.222 

.167166 

342 

10260 

513 

9747 

58308 

to such a state of unifor¬ 
mity in size as allowed 
them to be considered as 


t. 

2 

tt 

do. 

do. 

do. 

349 

10470 

523 

9947 

59505 

equal throughout and 
equal to each other. 












The experiments on 

n 

3 

it 

do. 

do. 

do. 

354 

10620 

531 

10089 

60355 

242 prove that the mean 
str’gth is 59247 lbs., and 












the irregularity between 

tt 

4 

ti 

do. 

do. 

do. 

345 

10350 

517 

9833 

58820 

experiments 1 and 3 is 
2047, or a little more 
than 1-29 of the mean 
strength. 

243 

5 

Nov. 

.753 

.222 

.167166 

340 

10200 

510 

9690 

57972 

From experiments 

<< 

6 

tt 

do. 

do. 

do. 

340 

10200 

510 

9690 

57972 

on this bar it appears 
that the mean strength 
was 58787 lbs., the dif- 

it 

7 

tt 

do. 

do. 

do. 

343 

10290 

514 

9676 

58480 

ference between expe¬ 
riments 1 and 5 is 2718 












or the irregularity a- 

tt 

8 

tt 

do. 

do. 

do. 

345 

10350 

517 

9833 

58820 

mounts to 1-21.6 part of 
the mean strength. 

tt 

9 

tt 

do. 

do. 

do. 

356 

10680 

534 

10146 

60690 


244 

10 

Nov. 

.753 

.222 

.167166 

332 

9960 

498 

9462 

56600 


tt 

11 

tt 

do. 

do. 

do. 

335 

10050 

502 

9548 

57115 

From these experi¬ 
ments it is seen that the 












mean strength of the 

tt 

12 


do. 

do. 

do. 

335 

10050 

502 

9548 

57115 

puddled bar was 57513 
lbs.—the greatesc differ- 









504 

9576 

57285 

ence,that between expe- 

ti 

13 

“ 

do. 

do. 

do. 

336 

10080 

laments 1 and 6, is 2390, 
or almost exactly 1-24 of 
the mean strength. 




1510 

9690 

57972 

tt 

14 

tt 

do. 

do. 

do. 

340 

10200 

tt 

U 

“ 

do. 

do. 

do. 

340 

10380 

51S 

9861 

5899C 
















































234 


Results. — 1 . The specimen which had been made from refinery bloom 
reduced to a bar 3 inches wide by 1 thick, piled 4 high and twice weld¬ 
ed, proved the strongest. Not only did it exhibit the high mean result 
of 59247 pounds to the square inch, but the consistency and uniformity of 
the metal were such as to show between the highest and the lowest results 
a difference amounting to only 3.4 per cent, of that mean. 

2. The specimen which had undergone two weldings, but had not been 
drawn into a bar and piled, was inferior to the preceding, giving a mean re¬ 
sult of 58787; and the difference between the extremes exceeds 4.6 per 
cent, of that amount. 

3. The specimen manufactured from puddled iron, rolled at the first ope¬ 
ration into a bar 3£ inches wide by 1 inch thick, cut and piled 4 tier high 
and then twice welded and rolled into bars little more than of an inch in 
thickness, was obviously designed by the manufacturers to correspond in all 
particulars with No. 1, except that the latter was from the bloomery, and 
the other (No. 3.) from the puddling furnace. The mean absolute strength 
of this specimen was decidedly less than that of either of the preceding, 
being only 57613 pounds, while the variation from uniformity was 4.1 per 
cent, of its mean strength. 

Effects of Piling into the same Plate , Iron of different degrees of fineness. 

It is believed to be a practice, not unknown among the manufacturers of 
boiler iron to combine into the same slab, and subsequently to roll into plate, 
iron of different qualities. In such cases the want of homogeneousness 
may manifest itself in a variety of ways. The different kinds may not be 
equally welded together throughout, and may consequently exhibit flaws at 
the surfaces of lamellation. They may hf» very unequally extensible under 
the same force, and while the outer ply of metal may, in turning a flanch, 
remain unbroken, the interior one may be greatly reduced in strength. They 
may be of different specific gravities and mislead the purchaser, who looks 
only upon the exterior face of the plate, and judges of its value by the good 
appearance of the latter, and the weight of the whole per square foot under 
a given thickness. 

By a reference to table XXXIII., in experiments on bars 39 and 41, it 
will be seen that a considerable defect, of the nature above alluded to, was 
exhibited, and the low results given in those cases, (40600 and 37700 lbs. 
per square inch) afford conclusive evidence of the bad quality of boiler plate 
in which such defects of welding between the laminae exist. 

In table XLIX., experiment 16, another example of the same kind occurs, 
in which a decided difference of appearance in the fracture showed itself 
between the interior and exterior folds of the metal. 

Effects of the Rivets on the Total Strength of Boilers. 

In whatever manner the parts of a steam boiler are united, the rivets 
which form the junctures being substituted for portions of the metal cut 
away to receive them, are of necessity so much deduction from the strength 
of the entire sheet, and unless we can suppose that the strain brought upon 
the rivet by the manner of setting it, when hot, and in that state making so 
close a bearing as, when cold, to contract and create a pressure that shall 
furnish an adhesion by friction between the overlapping surfaces, equal in 
amount to the strength taken away by the line of rivet holes, we cannot in 


235 


computing the absolute strength of any steam boiler, safely rely on more 
than the portion of metal which remains in the intervals between the holes. 
That the requisite amount of friction could not, under the circumstances 
which practice assigns to the case, be produced in the manner supposed, is 
easily demonstrable, since, for that purpose, the friction on two square inches 
of surface, (the amount which on each side of the line of rivets could possibly 
be available for this purpose,) must be equal to the strength of the part cut 
away, which seldom falls short of | of an inch. If we could suppose the 
rivet of this size so strained by hot working and shrinking as to exert #of 
its entire strength or what would be just sufficient to produce in it a perma¬ 
nent elongation, then as its area of section would be .3068 of a square inch, 
admitting the iron of which it was made to be capable of bearing 55000 lbs. 
to the square inch, we should have an actual pressure of 55000 X £x *3068 
=11249 pounds to be distributed over 4 square inches, giving for each of the 
two sheets 5624 pounds of pressure, the friction of which is to counteract 
the cutting away of T 5 g- of its substance. 

If we suppose the plate to have the same strength per square inch as the 
rivet, and | of an inch in thickness, two-thirds of the strength of the part cut 
away (| of an inch wide,) would be 5726 pounds. From this it is evident 
that for a weakening of 5726 pounds, we have only the compensation of 
the friction produced by a pressure of 5624 pounds. That fractures not 
only do take place along the lines of rivets when violent explosions occur, 
but that incipient fractures and permanent elongations are presented at the 
spaces between the rivet holes, is evinced by the appearance of the holes 
themselves elongated by strains and especially by overheating in the vicinity 
of the juncture. Examples of this are found in Table XCVIII. 

In a piece of boiler iron which had been some years in use, and which 
from overheating, in consequence of the collecting of a quantity of sediment 
in the part immediately above the fire, had become locally swelled into a 
protuberance reaching nearly the breadth of a sheet and from nine to ten 
inches in the direction of the curve, the rivet holes on both sides of the 
sheet, opposite to the protuberance, were found to be elongated as in the 
following table. All those on the side nearest to the summit of the protu¬ 
berance, were found to have cracks running out in different directions, and 
in some cases, nearly traversing the entire space between the two adjacent 
rivets. (See the figure, page 238.) 

Within half an inch of the first five rivets, and parallel with their line, a 
strip a, one inch wide, was cut from this piece of boiler, and tried at several 
filed sections. The report of these trials will be found in Table C. from 
which it will be seen that the portion nearest to the protuberance, and which 
had been reduced in thickness by the stretching, possessed much less 
strength per square inch than that which was still of the original thickness 
of the sheet. The surface of this bar, when the oxide had been removed, 
presented a distinctly spongy or honey-comb appearance, having many 
minute cells, which being developed by the shears were seen to be nearly 
filled up with oxide. The committee took an opportunity of making direct 
trial of the diminution of strength by rivetting. A bar of iron of an inch 
wide and .134 inch in thickness was rivetted together at a lap six inches 
long, by 12 rivets, each .205 inch in diameter, in two rows along the length 
of the bar, but alternating with each other in a zigzag course, the rivet near 
one edge being about one-third of an inch in advance, along the length, of 
the preceding one on the opposite edge. 

20* 


236 


TABLE XCVIII. 


Effect of unequal strains on rivet holes. 



p 

.®i*2 S 

1 S. 


te 

a 

O) 

g«c a ' 

C O.O-a 

.3 <D 

2 o .5 . 


© 

JZ 

JS 

M 

as 

M 1) D 1) 

52 v tS 
■5 »-a ► 


w 

CD 

> 

Cm 

O 

** fe 

O) 

o > •3'S 

REMARKS. 

'u 

<m 

O 

c 

O 

*4-» 

v v <u 

ji co u 

d a a « 


6 

& 

Po 

holes. 

Ler 
axis c 
ingii 
wards 
tion. 

Q. ZZ 
_).2 4- i, 

* is j= 

U) P 




Inch. 

Inch. 

Refer to fig., page 238. 


At the 



f The centre of the rivets in this piece of boiler iron 


part of 
the plate 
nearest 

.750 

.700 

I were 2 inches apart. Two cracks proceeded from 

i 

< this hole, one towards the interior of the sheet 4-10 


to the 
swelling. 



) inch long, the other towards the next rivet, 9-10 
kinch long. 

2 

Do. 

.735 

.650 

C An oblique crack proceeding gradually towards 
the interior but more rapidly to the next rivet, 9-10 
C inch long. 





3 

Do. 

.740 

.700 

C Crack proceeding towards the next rivet $ inch in 
£ length. 

4 

Do. 

.705 

.670 

C Two craGks proceeding in opposite directions, one 
£ 2-10 inch, the other 3-10 of an inch. 

5 

Do. 

.750 

.705 

C These cracks proceeding from the periphery of this 
hole, each from 3 to 4 tenths of an inch in length. 


At the 





part of 
the plate 




6 

most re- 

.725 

.700 

No cracks observable. 


frora 

swelling. 




7 

Do. 

.715 

.700 

Do. 

8 

Do. 

.675 

.645 

Do. 

9 

Do. 

.690 

.665 

Do. 

10 

Do. 

.665 

.665 

0 This hole appears to be the only one which retains 
k its original size and shape. 


The above described compound bar broke with an oblique section 1.05 
inch long, passing through two rivet-holes. 

The strength computed on the area of cross section was 52580 pounds, 
which reduced to the area of the actual oblique section is 45068 per sq. inch. 

The same bar afterwards broken at a point six inches from the foregoing 
fracture, exhibited a strength of 66027 pounds. If we conceive the diameters 
of two rivets deducted from the cross section there remains but .49 of an inch 
in the breadth of the strap of iron which supported an effective strain of 
6341 pounds. But the diagonal section of fracture had an area, after de¬ 
ducting the diameters of two rivet holes, of .64X. 134=.08576, whereas at 
the place of fracture, six inches distant, the area was . 113529. The effective 
strain which broke the bar in this latter case was 7496 lbs. Applying this 
as a standard to the actual section of fracture at the rivets, we have the fol¬ 
lowing calculations :— 

1. For the weakening effect of cutting away the metal at the rivets* 
.113529 : .1407 : : 7496 : 9290=the effective strain which would have been 
borne by a section of this metal, 1.05 inch wide and .134 inch thick, had 
none been cut away to make room for the rivets. But the actual area left was 


\ 
















237 


only .08576- Hence .113529 : 08576 :: 7496 : 5662 which ought to have 
been borne if no strengthening influence had been exerted by the rivets. 
The difference, or 9290—5662=3628, is the reduction of strength by cut¬ 
ting out the two cylindrical holes; but the actual effective strain was 6341. 
So that the weakening effect is in fact 9290—6341=2949. 

2. The strengthening effect of the friction is 6341—5662=679. 

Construction of Cylindrical Boilers and Flues. 

In connection with the subject of rivetting it may be remarked, that unless 
a due regard to the form of the parts of a boiler be observed in constructing 
it, and a due attention to the rivet holes in the different pieces, the strains 
incidental to the boiler in its regular use, may be made more dangerous than 
that which would arise from the mere elastic energy of the steam alone. The 
usual practice in constructing cylindrical boilers and flues is to make the 
portions in the form of frusta of cones, the smaller end of one of which 
entering the larger end of the next, is rivetted in such a manner as to turn 
all the outer laps in the direction of the fire end of the boiler. It is evident 
that in such a construction the several plates which constitute a single ring 
of the boiler must have the lines of rivets along their ends placed in converging 
right lines and those along the sides or longest edges, in circular arcs of 
different radii. If in any case these lines are inconsistent with the positions 
of others to which they are required to conform, the holes must either be 
rimmed out, or the sheet unduly strained in attempting to force a conformity 
of positions. 

In every case in which a just construction by the aid of previous calcula¬ 
tion is obtained, the centres of the rivet holes are the points from which our 
calculations must commence. 

It is obvious that the diameter of the cylindrical, or rather of the com¬ 
pound conical, shell, must constitute one element of the calculation, the 
breadth of the sheets a second, and the thickness of the metal a third. From 
these data may be found the radii of the curves in which are to be placed 
the rivets, and also the convergency of the two straight lines along the two 
ends of each sheet. The difference in the exterior diameters of the two 
ends of each frustum must at their respective rivet-lines be equal to twice 
the thickness of the metal. The larger arc for the rivet holes must manifestly 
be described by a longer radius than the smaller, and the difference of the 
two radii is the breadth of the sheet between the curves. 

The larger radius will in every case be found by adding to the mean ex¬ 
terior diameter of the boiler in inches , the thickness of the plate in the 
same denomination , multiplying the sum by the breadth of the plate , and 
dividing the product by twice the thickness of the plate* 

Effects of use and long exposure on the strength of boiler-iron. 

This topic may be regarded as one of the most important which came 
under the notice of the committee. To treat it in all its bearings would 
demand far more of time and means that were at our disposal. 

* Thus putting D=the exterior diameter of the boiler, 

° t =the thickness of the metal, 

b — the breadth of the sheet between the two ares of rivets, 
^=the length of the greater arc which will reach round the larger 

end of the frustum, 

“ less l)o. 

/2=the radius of the greater arc, 
r== “ less; so that R — r=b, 

also rt=3.1416. 


238 


Table C. contains the results of trials on four bars or strips cut from 
pieces of plate which had been long in use, and which were more or less 
visibly affected by the strain, or by the action of water and steam to which 
they had been subjected. They were cut lengthwise and crosswise re¬ 
spectively from the sheets out of which they were taken, one bar in each 
direction out of each sheet. 

The two strips, Nos. 245 and 246, taken from a specimen of plate which 
had been burst, are represented in position by the dotted lines in the accompa¬ 
nying sketch. The length of the specimen is the original breadth of the sheet 
and lay as usual in the direction of the length of the boiler, 30 inches in 
diameter, from the bottom of which near the fire-end this piece was taken. 
Hence the shorter strip (a) is a length sheet strip, and the longer (&,) a cross 
sheet strip. 

Agreeably to what has already been shown, the former possessed the 
greater strength, but the second experiment upon it made at the point 
•m, where the swelling commenced, was found, as shown in the table, con¬ 
siderably weaker than the sections near the two ends of the strip. 

The amount of the swelling on this specimen of iron may be seen by the 
two sketches, page 239, one of which is longitudinal and the other transver¬ 
sal, and the lengths of the ordinates, from lines at right angles to each other, 
and both passing over the centre of the swelled part, at b will be found in the 



Then, since the arcs are similar, A : a :: R : r and A—a : A :: R r : R. But 

A=rt (2)4*0 ar) d a =7t (2) —t .) Hence A — n—rt (2)-f-/)— H (2)—/) = 2 rt /. 
Hence by the above proportion and putting b for R—r we obtain 2 nt : n (2)4-/) 

:: b : R , from which results R= A ( ' D ^ rt \ and r= 6 . As there must be 

2 / 2 / 

the same number of rivet holes in each arc, a knowledge of the lengths of the re¬ 
spective arcs and of the number of rivets to be placed round the boiler, determines 
their distances from each other, on the two curves respectively. The accompany¬ 
ing figure represents the arrangement of the rivet-holes in a plate of metal adapted 
to constitute a part of a cylindrical boiler, with the centre c, and radii cy and cx of 
the two arcs of rivet-holes. 

























































































































































































































































































































































239 


accompanying table. The ordinates on the inside or concave part of the 
plate, commence Fig. 1 from the centre of the rivet holes nearest to the 
place of rupture b. The points on the two axes were 1.075 inches apart. 

TABLE XCIX. 


No. of mark on the line 
lengthwise of specimen. 

Ordinate or distance 
of the line from the bot¬ 
tom of the cavity in 
inches. 

REMARKS. 

No. of mark on the line 

transverse to the curva¬ 

ture of the piece. 

Ordinate or distance 

from the co-ordinate to 

the inner surface of the 

swell. 

REMARKS. 

1 

.150 



1 

.700 


2 

.500 



2 

1.425 


3 

.945 



3 

2.200 


4 

1.430 



4 

2.720") 


5 

2.000 


The rupture was opposite 

5 

2.960 ( 

C 1 he rupture was oppo- 

/ sit.ft to thpsp mark^ 

6 

2.075 } 


to these marks and the 

6 

2.320 j 


7 

2.350 C 


distances could not be 

7 

1.745 


8 

1.975 j 


measured with the same 

8 

0.940 


9 

1.870 

Lprecision as the rest. 

9 

0.390 


10 

1.600 



10 

0.000 


11 

1.360 






12 

1.115 






13 

0.940 






14 

0.665 






15 

0.520 






16 

0.395 






17 

0.350 






18 

0.265 






19 

0.145 






20 

.080 


• 





The original distance in the line ac, Fig. 1., was 22£ inches. The length 
of the curve abc by actual measurement was found to be 24.6 inches. 
Hence the extension of the metal in this direction had been 2 1-10 inches 
in 22 5-10 or T |. T of the whole length. 

Fig. 1. 


I 




The length in the direction of the curve def, Fig. 2., was originally 10.6 
inches. Actual measurement over the curve dbf, gave the length 12 inches, 
showing an elongation of fibres in this direction equal to 1.4 inches in 10.6 
or of their whole original length. This greater extension of the 
fibres in the longitudinal direction of the sheet, accords with what has al¬ 
ready been proved by direct trials on bars cut from new plates. 




















240 


TABLE C. 


Experiments on old boiler iron, Nos. 97, 98, 245 and 246. The two 
former manufactured by Lukens , and the two latter uncertain , all 
having been some time in use , and visibly affected by the action of heat 


No. of the bar. 

No. of the exp’t. 

DATE. 

Breadth of the sec¬ 
tion of fracture before 
trial. 

Thickness of the sec¬ 
tion of fracture before 
trial. 

Area of the section 

before trial. 

Temperature. 

Breaking weight. 

Breaking weight X 

leverage. 

Friction. 

97 

1 

1836. 
Feb. 13. 

.785 

.197 

.154645 

45° 

273 

8190 

409 

« t 

2 

<i 

1.000 

.215 

.215000 

45 

349 

10470 

523 

a 

3 

it 

1.100 

. l 

C.100? 

1.200 5 

.165000 

45 

282 

8460 

423 

a 

4 

Feb. 27. 

.736 

.217 

.159712 

41 

285 

8550 

427 

98 

5 

Feb. 13. 

.720 

# 

.194 

.139680 

45 

238 

7140 

357 

a 

6 

Feb. 27. 

.705 

.214 

.150870 

41 

275 

8250 

412 

it 

7 

a 

1.000 

.182 

.182000 

41 

338 

10140 

507 

it 

8 

it 

1.051 

.220 

.231220 

41 

373 

11190 

559 

245 

9 

Mar. 21. 

.661 

.165 

.109065 

50 

207 

6210 

310.5 

ii 

10 

it 

.732 

.141 

.103212 

50 

170 

5100 

255 

it 

11 

it 

.731 

.181 

r 

.132311 

50 

228 

6840 

342 

246 

12 

Mar. 26. 

.704 

.182 

.128128 

51 

206 

6180 

309 

« 

13 

H 

.721 

.182 

.131222 

51 

219 

6570 

328 

<« 

14 

a 

.686 

.182 

.124852 

51 

212 

6360 

318 

it 

15 

11 

.693 

.183 

.126126 

51 

231 

6930 

346.5 






































241 


TABLE C. 

f or corrosion. The two latter were from a specimen in which was a 
■< rupture in consequence of the collection of a sediment over the part ex- 
imposed to the fire. 


• 

M 

*4 

z 

PL 

to 

jg 


CS 

u 

to 

O 

> 

c 

• . 

.C O 

Sog 

REMARKS. 

5e 

W 

fi u 

g § 

M a* 

to 


7781 

50314 

C This strip was cut crosswise of the sheet,—filed section, 
l edges and faces both filed. 

9947 

46265 

Original section produced by the shears. 

8037 

48103 

C Fracture at a part deeply corroded. The thinnest place be- 
\ fore trial was found but one-tenth of an inch thick. 

8123 

50860 

C The edges of this section of fracture were deeply filed, 
i and the oxide was removed from the faces of the bars. 

9 * 

6783 

48561 

Filed on both edges and faces. Cut lengthwise. 

7838 

51952 

C Filed deeply on the edges. Oxide barely removed from 


£ the faces. 

9633 

52928 

The edges barely straightened, much filed on the faces. 

10631 

45982 

Edges barely straightened by filing—faces unfiled. 

5989.5 

54000 

C Deeply filed on the edges. Oxide removed from the faces. 
^This strip cut lengthwise of the rolling. 

4845 

46942 

C This part of the bar had been over-heated, and stretched. 

1 Deeply filed as above. 

6498 

49111 

Deeply filed, and oxide removed. 

5871 

45821 

C This strip cut crosswise from the ruptured specimen. (See 
£ figure on page 238.) Filed and scale removed. 

6242 

47568 

Filed and cleared of oxide as above. 

6042 

48465 t 

Do. 

6583.5 

• 

52205 

Do. 














242 


The two specimens, Nos. 97 and 98, Table C., were deeply corroded in 
certain parts, indicating the existence of local chemical actions arising proba¬ 
bly from inequalities in either the purity, or the mechanical structure, of 
the sheet. 

In both sets of the above trials on old boiler-plate it will be observed that 
though the mean strength is low, being under 50000 pounds per square 
inch, yet the principle is still preserved which assigns a greater tenacity in 
the longitudinal than in the transverse direction of the rolling. The differ¬ 
ence, in this respect, between Nos. 245 and 246 is 50017—48515 or 3 per 
cent, of the strength of the transverse strip. 

Between Nos. 97 and 98 the difference is somewhat less. 

Effect of Annealing on the tenacity of Iron. 

In a variety of cases the committee have endeavoured to extend the range 
of their experiments so as to embrace the condition of a steam-boiler which 
without being exploded has suffered from the exposure of its fire-surface 
when destitute of a due supply of water, to the action of heat above redness. 
In a few of the trials at elevated temperatures, this point was attained or 
surpassed, and the subsequent trials on parts near the places of fracture in 
such cases, gave evidence that the condition of the metal in regard to tena¬ 
city had been altered. In the case of bar No. 13, Table XXXI., it will be 
observed that annealing, which in that instance was produced by the folding 
over of the ends of the bar to obtain a more certain hold by the wedges, 
determined at once the place of fracture. 

On specimens 199 B and 199 C, Table CII., which were wires manufac¬ 
tured at Phillipsburg from Juniata iron, were made several experiments to 
ascertain its mean tenacity, in the ordinary state of the article. On other 
pieces of the same wires the process of annealing at high temperatures was 
performed. The results show that the maximum effect of annealing on one 
of the sizes was a diminution of 27.5 per cent., and on the other 46 per 
cent, of the original strength. 

In these instances the annealing was performed in a common smith’s fire, 
without using any other precaution to defend the wire from oxidation than 
merely covering it with cinder. 

This prevented, for the most part, any action of the air on the wire during 
the short time of its remaining in'the fire. But to obviate altogether the ob¬ 
jection that oxidation might have some share in producing the weakening 
effect, several specimens of iron were, after being carefully gauged, weighed 
and, having their specific gravities taken, rolled up in several folds of clean 
sheet iron; the ends of the folds turned over and hammered flat, to prevent 
access of air, and the whole then exposed for 15 or 20 minutes to the blast 
of a smith’s fire, gradually raising it to a very high welding heat. In this 
state the package was withdrawn from the fire, often exhibiting one or two 
folds of the sheet iron cut through by the blast, but in no case extending to the 
enclosed specimens. When taken from the fire it was immediately buried 
in dead cinders, where it was allowed to remain until quite cold. The 
wrapping of sheet iron was then removed, and the specimens generally found 
with no visible change except a slight discolouration by black oxide of the 
metal, insufficient, however, to affect sensibly the weight of the specimen. 

The five trials on Nos. 224 C and 254 D were among those which had 
been reduced or constricted by straining before the specimens were annealed. 


243 


TABLE CL 


Wrought iron annealed at different temperatures. 


| No. of the comparisons. 

No. of the specimen 

on which tne trial was 

made. 

No. of the table con¬ 

taining the results on 
each specimen. 

Strength at ordinary 

temperature before an¬ 

nealing. 

Temperature at which 

the annealing took 

place. 

Strength at the an¬ 

nealing temperature. 

Strength after anneal¬ 

ing and cooling. 

Rate of diminution 

in strength by anneal¬ 

ing. 

1 

152 

LI. 

57133 

1037° 

37764 

55678 

.025 

2 

214 

LXII. 

59219 

1022 

37410 

46612 

.213 

; 3 

227 

LIV. 

53774 

1111 

27604 

52186 

.029 

4 

226 

LIII. 

52040 

1142 

18672 

44720 

.140 

5 

227 

LIV. 

53774 

1155 

21967 

45597 

.152 

6 

229 

L VI. 

53185 

1159 

25620 

46212 

.131 

7 

227 

LIV. 

53774 

1187 

21919 

45027 

i 

.162 

8 

226 

LIII. 

52040 

1192 

29703 

43154 

.170 

9 

226 

LIII. 

52040 

1237 

21298 

44165 

.151 

10 

226 

LIII. 

52040 

1245 

20703 

38843 

.253 

11 

224C. 

LXXII. 

48407 

Bright welding heat. 


36052 

.255 

12 

224C. 

LXXII. 

48407 

Do. 


39333 

.187 

13 

224D. 

LXX1II. 

48830 

Do. 


35889 

.265 

14 

224 D. 

LXXIII. 

48830 

Do. 


36706 

.248 

15 

224C. 

LXXII. 

48407 

Do. 


38676 

.201 

16 

19 

XXXII, 

52912 

Do. 


44191 

.165 

17 

199B. 

CII. 

73880 

Low welding 
heat. 

• 

53578 

.275 

18 

199A. 

LXIV. 

76986 

Bright welding 
heat. 


50074 

.349 

19 

. _ 

199C. 

CII, 

89162 

Low welding 
heat. 


48144 

.460 


21 











































































































































244 


TABLE CII. 

Experiments on two specimens of wire, Nos. 199 B. and 199 C.~) 
Manufactured at Phillip sburg, Pa., from Juniata iron. One specimen $ 


No. of the exp’t. 

Diameter of the wire. 

Area *of section of 

the wire before trial. 

Temperature when 
tried. 

Breaking weight in 

the scale. 

Breaking weight X 

l leverage. 

Friction of the ma¬ 

chine. 

Effective strain. 

1 

inch. 

.190 

square inch. 
.0283526 

70° 

73. 

2190 

109.5 

2080.5 

2 

do. 

do. 

70 

73. 

2190 

109.5 

2080.5 

3 

do. 

do. 

70 

74.5 

2235 

111.7 

2123.3 

4 

do. 

do. 

70 

74. 

2220 

111. 

2109. 

5 

do. 

do. 

70 

73. 

2190 

109.5 

/ 2080.5 

6 

do. 

do. 

• 76 

49.5 

1485 

74.2 

1410.8 

7 

do. 

do. 

76 

54.5 

1635 

81.7 

1553.3 

8 

do. 

do. 

76 

62. 

1860 

93. 

1767. 

9 

do. 

do. 

76 

61.5 

1845 

92.2 

1752.8 

10 

do. 

do. 

76 

61.5 

1845 

92.2 

1752.8 

11 

do. 

do. 

76 

52. 

1560 

78. 

1482. 

12 

do. 

do. 

76 

53.5 

1605 

80.2 

1524.8 

13 

do. 

do. 

76 

52.5 

1575 

78.7 

1496.3 

14 

do. 

do. 

76 

54. 

1620 

81. 

1539. 

15 

do. 

do. 

76 

54.5 

1635 

81.7 

1553.3 

1 

.156 

.0191127 

76 

60. 

1800 

90. 

1710. 

2 

do. 

do. 

' 76 

60. 

1800 

90. 

1710. 

3 

do. 

do. 

76 

59.5 

1785 

89.7 

1695.3 

4 

do. 

do. 

76 

60. 

1800 

90. 

1710. 

5 

do. 

do. 

76 

59.5 

1785 

89.7 

1695.3 

6 

do. 

clo. 

77 

32. 

960 

48. 

912. 

7 

do. 

do. 

77 

32.5 

975 

48.7 

926.3 

8 

do. 

do. 

77 

32.5 

975 

48.7 

926.3 

9 

do. 

do. 

77 

33.5 

1005 

50.2 

954.8 

10 

do. 

do. 

77 

33.5 

1005 

50.2 

954.8 

11 

do. 

do. 

77 

34.5 

1035 

51.7 

983.3 

12 

do. 

do. 

77 

35. 

1050 

52.5 

997.5 


































245 


TABLE CII. 

of each size , broken up cold , and without annealing, the others annealed 
and cooled , either in cinders or in water. 


Strength in lbs. per 

square inch. 

Mean strength in each 

state. 

\ 

REMARKS. 

73379 


The first five experiments were made on specimen 199 B,of 

73379 

74880 

74386 

73379 

73880 

the wire, unannealed. 

49760 


This and the four following experiments were made on a spe- 

54786 


cimen of the wire of about the same length as the above, an- 

62323 


nealed by heating to redness, and then buried in dry ashes 

61819 


until cold. 

61819 

58101 

Broke in the gripe of the wedges. 

52268 


This and the four following were made on a specimen of the 

53781 


same wire as the two above mentioned, annealed at redness and 

52775 

54281 

54786 

53578 

immediately quenched in cold water. 

89469 


This and the four following experiments, were on the small- 

89469 

88703 

89469 

88703 


est size of wire, 199 C., in its unannealed state. 

47714 

48360 

89162 

• 

This and the two following were made on wire of the same 


size, and from the same piece as the above, annealed and buried 

48360 

48144 

in ashes. 

49958 


This and the three following were on the same size of wire, 

49958 

51449 

52192 

50889 

annealed and immediately quenched. 


























246 


No essential change of specific gravity from annealing was detected, except 
in the case of a piece which had been beforehand excessively hammer-hard¬ 
ened. This appeared to have been slightly diminished in density by the an¬ 
nealing process. When the specimens treated in this manner had been pre¬ 
viously strained nearly to the limit of their tenacity, and their original areas 
of section consequently much reduced, the precaution was taken to re¬ 
gauge them before annealing, so that we could employ the then existing 
areas of section, instead of the original ones, as the basis of calculation for 
the strength per square inch. This course was followed with Nos. 224 C 
and 224 D. 

Calculating the strengths on the areas of these bars taken just before an¬ 
nealing, they were found as follows: 

Instead of 36052 we obtained 




tt 


it 


a 


a 


a 


t1 


tt 


39333 

35889 

36706 

38676 


Cl 


It 


ii 


a 


a 


tt 


a 


a 


45090, 

41980, 

42700, 

43200, 

41980. 


From table Cl. it appears, that, computing the strength in the com¬ 
parisons from 1.1 to 15 inclusive on the area before annealing, and ex¬ 
cluding Nos.l and 3 of the series, as not made at a sufficiently high tempe¬ 
rature to effect the purpose, we get the mean tenacity of iron, by seventeen 
comparisons after annealing, equal to 45117 lbs. to the square inch. 

In a considerable number of cases where trials were made at high tempe¬ 
ratures, especially those above 1000°, the iron was left in an annealed state. 
In several of these the effect of the process is nearly as striking as where 
the heating had extended to the point of welding. 

In other cases the difference between the strength previous to annealing, 
and that exhibited afterwards, was so small, that it was difficult to refer it 
to any other cause than the original inequalities of structure. 

It will be seen that, from Experiment 3 to Experiment 11 (Table Cl.) the 
loss of tenacity by annealing follows very nearly the order of the tempera¬ 
tures at which the process was performed. 

That boilers do, in the course of ordinary practice, frequently become an¬ 
nealed there can be little doubt. The four specimens of old boiler-iron al¬ 
ready spoken of, indicate clearly the existence of such a state. The mean 
strength of those specimens by 15 experiments was 49278 lbs., while the 
mean minimum strength of the four bars was 46252, quite within the range 
of the tenacity of iron annealed at a red heat. Hence, unless we can be 
certain that a boiler will be entirely secure from this process, we shall not 
be warranted in calculating its strength at any greater amount than about 
46000 pounds per square inch, and of this amount but two-thirds can be 
assumed as a safe basis of calculation, being that at which permanent change 
of form would take place. 

Your sub-committee have at length brought to a conclusion the research 
which has so long* occupied their attention. The foregoing pages pre¬ 
sent as concisely as the case seemed to admit, the facts which their in¬ 
vestigations have elicited, in regard to the several inquiries, Principal, 
Incidental and Subsidiary, stated in the preliminary part of this report. 
The great interest of the subject required that the utmost care should be 


* This sub-committee was appointed January 4, 1831, and preparations for the 
experiments immediately prosecuted.—The trials of tenacity were commenced 
April 4, 183*2. The last experiments were made January 5, 1837. 


247 


exercised to prevent error. Hasty and unwarrantable conclusions were to 
be avoided. It has been our sincere desire to meet every just expectation 
in regard to the practical usefulness of the information of which we were in 
search. It would be presuming too far to suppose that in so extensive a 
mass of calculations we had escaped all error. So many steps of each pro¬ 
cess, have, however, been preserved, that verifications will be easily made. 
Speculations, merely scientific, have been deemed inappropriate to this re¬ 
port, and we now abstain from swelling it with repetitions of statements 
already made, or with any matters not strictly pertinent to the subjects em¬ 
braced within the views of the general committee. 

WALTER R. JOHNSON. 

BENJAMIN REEVES. 

N. B. —Prof. A. D. Bache, the remaining member of the sub-committee, 
being absent from the country at the time of making this report, we regret 
that it is impracticable to submit it to him for inspection and signature. 

In the course of this inquiry we have been indebted for valuable personal 
assistance to several friends of the useful arts, among whom we would parti¬ 
cularly mention the late Benjamin Say, Esq., and Messrs. James M’Crea, 
James Barnet and Joseph Brezinski. The last named gentleman repeated 
and verified many of the calculations as well as aided in various experiments 

Note. —Mr. Telford has made an interesting series of experiments on the strength of 
wire, an account of which is found in Mr. Barlow’s treatise on the strength and 
stress of timber, page 254. 

The same gentleman made various experiments on bars and bolts of iron, de. 
tailed in the same work. 

He also attended to the successive elongations of bars under different weights, 
and noted the amount of recoil or contraction when relieved from strain. 

Captain S. Brown has also furnished to Mr. Barlow, a series of highly interesting 
experiments on the strength and elongation of iron bolts. 

The mean result of three experiments by Mr. Brown on cast-iron was 18564 lbs. 
to the square inch. 

Mr. Hodgkinson has published in the third report of the British Association, 
three results of experiments on the same material, which make its strength 17136 
lbs. per square inch, while the three experiments of the committee of the Frank. 
Inst., which were considered fair, indicated in the bars a strength of 20834 lbs. 

Mr. Brunton and Mr. Brunei, have each engaged in this interesting department 
of inquiry and given the results of experiments on a large scale which will be 
found in the work of Mr. Barlow already cited. 

Mr. E. Martin, formerly of the Polytechnic school, has given in the Annales des 
Mines, Vol. V., a series of experiments executed in France, under the orders of 
M. Barbe, on round rods of iron, 18 or 19 feet long and 2 inches or more in diame¬ 
ter, made with a view, in part, to determine the recoil when released from strain, 
and the actual amount of elongation under each weight to which it was subjected. 

In the same volume of the Annales des Mines, M. Vicat has a paper referring 
to, and controverting some of the positions of M. Martin, but not affecting the 
statements respecting the experimental operations just referred to. 

In the same work, Vol. VI., are contained some interesting statements by M. 
Payen, respecting the manufacture of wire, in which the relative ductility before 
and after annealing is established. 

In the Annales de Chimie et de Physique for Sept. 1833, is a valuable paper by 
M. Vicat, showing the influence of time on the gradual extension of wires under 
different weights. Each of his experiments occupied nearly three years. 

The quantity by which iron extends under different degrees of tension, and on 
the recoil when relieved from strain, has been examined by Prof. Barlow. See 
Journal Fran. Inst. Vol. XVI. p. 124, &c. The relation between the effect of 
straining and elongating a bar by mechanical means, and that of expanding it by 
heat, is also noticed. 


21 * 


248 


INDEX. 

* * 


Air, contact of, 

Alloying- of copper at 992°, 

Annealing 1 , effects of 

-, table of, at different temperatures, . 

Apparatus for high temperatures, . 

- for latent heat, . . ' . 

Arc on which elasticities were read, 


Page 54 
. 71 

240, 242 
. 243 

15 
. 41 

8 


Pars cut in different directions. 

Path for heating standard piece, 

-for hot metal or oil, 

Black, result on latent heat, obtained by 
Blake, H. & Co., experiments on iron manufactured by 
Ploomery treatment of iron, 

Boiler, cylindrical, construction of 

-of steam pyrometer, 

Boiler-iron, specific gravity of . 

—-, effects of use on 

-, strength of at ordinary temperatures, 

Brown’s results on tenacity, 

Brunei’s results on tenacity, 

Buffon’s results on tenacity, 


232 
. 20 
15 
43 

. 13, 96—107 
110 
. 237 

17 

. 232 

237 
. 79 

4, 247 
4 


Cable bolt iron, experiments on 

Callipers, proportional ..... 
Cast iron bars, how tried, .... 

--, experiments on ... 

Cast steel, experiments on . 

Chisel-edge fracture, ..... 
Clement on latent heat of steam, 

Comparison of different methods of making boiler-iron, 
Compound fracture, .... 

Condenser, experiments with 

-of steam pyrometer, 

Construction of cylindrical boders and flues, 

Constriction of iron, . ... . 

- in breadth and thickness unequal, 

-, table of .... 

Cooling apparatus, ..... 

—-of liquids by air, table of 

Copper, specific heat of 


152—157 

14 

15 

. 148 

158 
. 188 
43 
. 146 

121 
133 
. 19 

237 
. 224 

224 
. 222 
121 
56 
33 
















249 


Copper, strength of 

-, effect of increased temperature on 

-, gradual elongation of . 

-, tried at 32°, 

-, alloyed by melted tin, . 

-, extensibility of 

-, bar of, No. 1 . Made by 

2 

3 

4 * i • 

5 

6 

7 

8 . . 


John M’Kim 
do. 


Jr. & Sons, 


do. 

do. 

do. 

do. 

do. 

do. 


Counterpoising, method of weighing by, adopted, 

Counterpoise, revolving 

Crucibles for graduating thermometers, 

Cylindrical boilers and flues, 


Page 57 
74 
59, 61 
61 
. 71 

78 
. 58 

60 

. 62 
64 

. 66 
68 
. 70 

72 
41 
18 

. 22 
237 


Delaroche and Berard on specific heat of vapour, . 
Despretz on latent heat, 

Diminution of area at the moment of fracture, 
Divellent and quiescent forces in steam-boilers, 
Dulong and Petit’s results, . 


43 

43 

224 

3 

39 


Effect of increased temperature on copper, 

Elasticity after some hours of strain on a bar, 

-, careful experiments on 

”*■—of iron, ..... 

-, second method of observing . 

-, table of 

-of iron after partial fracture, . 

-of machine, .... 

-, law of ..... 

Ellicotts, iron furnished by ... 

Ellicott, Evan T. & Co., experiments on iron made by . 

Ellicott, S. E. H. & P., experiments on iron made by 
Elongation, experiments on,59. 61. 103. 105. 141. 143. 145. 163. 

-, progress of .... 

-, permanent, remarks on 

-,-, table of .... 

English boiler-iron, experiments on 
Expansion of iron by heat when under strain, 

Extensibility of copper, .... 

-of iron in two directions, 

-unequal in laminje of boiler-iron, . 

Extension, permanent with two.thirds of breaking weight, 


181. 183 


74 
119 
101 
218 

219 

220 
89 
10 
11 
13 

136—145 
118—133 
, 197. 201 
.130. 228 
226 
. 227 

134—135 
93 
. 78 

225 
. 93 

129 


Flaw, interior. ........ 133 

Flaws developed by straining iron, ...... 109 

Formula for tenacities of iron, ...... 218 

-- for diminution of tenacity, . . . . . .75 

- for the calculation of temperature at no tenacity, ... 77 

- for rate of cooling, . . . . . . .55 

_ for steam pyrometer, ...... 18 

__ for cylindrical boilers, ...... 237 

_ for specific heat of jars, ..... 31. 36 

~ ■ of iron, . ...... 37 

_for latent heat, . . . . ... . .42 

Fractures, compound ....... 224 



































250 


Fractures, two simultaneous 

• • 

• 


Page 121 

-, peculiar form of, in bars tried at high temperatures 


• 

125 

Friction of machine, subtractive 

• • 

• 


7 

-, how determined, 

• • • 


• 

8 

-, single and double 

• • 

• 


9 

-table of, for machine, 

• • • 


• 

9 

Furnace, suspended . . , 

• • 

. 


15 

.- used to regulate temperature, 

• • 


129. 137. 139 

Glass, mean specific heat of 

• • 

. 


. 31 

Gaugings, repeated 

• • • 


• 

. 126 228 

Gravity of parts in machine for tenacity how counteracted, 

• 


7 

-, specific, of iron, 

• • • 


• 

232 

Grubb, H. A. & heirs, experiments on iron. 

made by . 

• 


130, 186 

Hammer-hardening, experiments on 

• • 

. 


156-7 

Heat regulated by suspended furnace, 

• • • 


• 

91 

-visibly red in daylight, 

• • 

• 


. 137 

-, specific, tables of, 

• • • 


• 

. 24 to 35 

Heating apparatus, 

• • 

• 


15 

-by contact of air, . 

• • • 


• 

54 

-of liquids by immersed solids, . 

• • 

• 


48 

-, observations on . 

• • • 


• 

49 

-power of the atmosphere, how compensated, . 

• 


. 23 

Honey-comb appearance of old boiler iron, 

• • • 


• 

236 

Iron, bar of, No, 2 . . Mason & Miltenberger, 


. 80 

o 

O • • • 

do. 


• 

82 

4, 6 and 8 

« do. • 

• 


60 

9, 10 and 11 . H 

S. Spang & Son, 


• 

. 84 

14 

* do* • 

• 


. 86 

16 . 

do. 


• 

90 

17 and 18. 

• do* * 

• 


. 88 

19 . 

do. 


• 

92 

21, 22 and 23 

• do* * 

• 


. 88 

25, 27,30,32,35,37,39&41 Barnet Shorb, 

• 

94 

42, 43, 44, 46 and 48 

H. Blake & Co., 

• 


. 96 

49 . 

do. 


• 

104 

51, 53, 56 and 58 

. do. 

• 


. 98 

59, 60, 61 and 62 

do. 


• 

100 

64, 65. 68, 71 and 73 

. do. 

• 


. 102 

74 . 

do. 


• 

106 

75 and 78 

Schoenberger &. Son, 


. 108 

81, 83, and 84 

do. 


• 

. 112 

85, 86 and 87 . 

. do. 

• 


. 108 

88 . . . 

do. 


• 

148 

90 and 91 

• do • * 

« 


. 112 

94 and 95 . 

R. Lukens, 


. 

116 

97 and 98 

• do. * 

• 


. 240 

99 and 101 

Pennock, 


• 

148 

103 and 105 

Jackson, 

• 


. 148 

107,108, 111, 112and 120 R. Lukens, 


. 

116 

125,130,133,135 and 137 S. E. H. & P. 

Ellicott, . 

. 118 

142 and 143 

do. 


• 

122 

146 

. do. 

. 


. 126 

148 . 

do. 


• 

120 

149 

. do. 

• 


. 128 

150 . 

do. 


• 

130 

151 

. do. 

. 


. 120 

152 . 

do. 


• 

132 



















251 


Iron, bar of, No. 


154 and 157 
160, 162 and 164 
167 and 169 . 

171 and 174 
180 and 181 
182 
185 
191 


. do. 
do. 

. do. . . 

« do. . 

Furnished by R. Tyler, . 

. Super, 

. L. Morris 8c Co. 

. R. Tyler, . 

199 A (wire) Made by H. Phillips, 

199 B and 199 C do. . 

200, 201, 206, 207, and 208 furnished by G 

212 and 213 ... do 

214 . . . . .do 

213 a and 214a ... do 


Ralston 


215 

217 

218 A 

218 B 

219 A and 219 B 

220 A 

220 B 

221 A 

221 B 

222 A 

222 B 

223 A 
223 B 
223 C 
223 D 

223 E 

224 A 
224 B 
224 C 
224 D 
224 E 
226 

227 

228 

229 

230 

231 

232 

233 

234 and 235 

236 

237 

242, 243 and 244 


do 


made by J. Thompson, 

. Salisbury Iron Co 
do. 
do. 

do. . 

. do. 

do. 

. do. 

do. 

. do. 

Massey, 

. do. 

do. 

. do. 
do. 

Yeatman Sc Woods, 
do. 

. do. 

do. 

. do. 

E. T. Ellicott 8c Co. 

. do. 
do. 

. do. . 
do. 

(Russian bar,) 

(Swedish bar,) . 

(do.) 

Made by G. Valentine, 

. Yeatman 8c Woods, 

. H. A. Grubb 8c heirs, 
Valentine 8c Thomas, 

. (Uncertain,) 


245 and 246 

Iron, boiler, experiments on 

-, modes of making 

-, piled .... 

-, strength of, made by different processes. 

Iron, cable bolt, experiments on 

-Company, Salisbury, materials furnished by . 

-made by other processes than rolling into plate, 

Russian, experiments on 


-,specific heat of 


Irregularities of structure in copper. 

Irregularity in strength of bars not filed to uniformity, 


Page 122 
124 
. 120 
122 
. 148 
148 
. 148 

150 
. 158 

244 
. 134 

152 
. 154 

156 
. 150 

150 
. 192 

194 
. 196 

198 
. 200 
202 
. 204 

206 
. 208 
160 
. 162 
164 
. 166 
168 
. 170 

172 
. 174 

176 
. 178 
136 
. 138 
140 
. 142 

144 
. 180 
182 
. 184 

150 
. 150 

186 
. 233 
240 

80-109 and 112-195 
110 
. Ill 
147 
152—157 
13 

. 148 

189 
. 20 
75 
. 117 


Jars, glass, specific heat of 


27 

















252 


Johnson, Prof., steam pyrometer by 


Page 16 


Lamellations developed by straining piled bars, 
Laminae, distinct, in piled iron, 

Lamp applied directly to heat a bar. 

Latent heat of vapour, . 

-, apparatus for 

-, method of experimenting on . 

-, formula for 

-, Lavoisier on 

— - , table of 

Lavoisier on latent heat . 

Law of communication of heat to liquids by solids, 

-of diminution of tenacity of copper by heat, . 

-of heating and cooling by contact of air alone, 

Lukens, R., materials furnished by 
-, experiments on iron made by . 


95 
131 
. 173 

20 
. 41 

42 
. ib. 

43 

44 and 45 
43 
. 53 

75 
. 55 

13 

116-117 


Machine for proving tenacity, 

-, description of . 

Manufacturers of materials tried. 

Manufacture of boiler iron, .... 
Martin’s results on tenacity, 

Mason & Miltenberger, iron furnished by 

-, experiments on iron manufactured 

Massey, Mr. experiments on iron made by 
Materials whence obtained, 

McKim 8c Son, materials furnished by 

-, experiments on copper made by 

Mercury, bath of, 

Missouri iron, experiments on 
Mitchell, Dr., lamp by . 

Mixed pigs of iron, ..... 
Muschenbroek’s results on tenacity of iron, 


y 


5 

6 

. 13 

110 
4 
13 

80—83 
160—169 
12 
. 13 

58 

25, 26, 28 
160—169 
16 
190 
4 


No tenacity, meaning of the term 


74 


Pennock, iron furnished by . . • • • .13 

Perronet’s results on tenacity, ...... 4 

Phillips, H., materials furnished by . . . . . .13 

-, experiments on wire made by . . . . . 158—159 

Pig metal, different sorts of, used in making bar iron, .... 189 

-, table of the effects of . . . . . 191 

Piling various sorts of iron, ....... ibid. 

-, repeated ........ 232 

-different sorts of iron together, ..... 234 

Poleni’s results on tenacity of iron, . ..... 4 

Preparation of specimens, ....... 13 

Protuberance in old boiler iron, ...... 239 

Puddling iron for boiler plate, ....... 110 

Pyrometer, steam ........ 16 

-, standard piece of . . . . . .19 

-, used with new. revolving weight, .... 183 

Questions, principal stated ....... 4 

-, incidental and subsidiary, ..... 5 

Quiescent and divellent forces, ....... 3 


Ralston, A.8c G., materials furnished by, 

-, Gerard, experiments on boiler-iron furnished by 

Recoil of bars when relieved from strain, 

Red heat, temperature of 


. 13 

134-5 
149, 219 
137 



























253 


Red heat, effects of Page 173 

Rennie’s results on tenacity of iron and copper, .... 4 

Results of comparisons between bars of iron cut in different directions, . 232 

• -of experiments on bar iron, . . * 188 

-on latent heats, . . . . . . . .143 

-on specific heats, ....... 37 

Revolving counterpoise, . . . . . . .31 

Ritner, P., materials furnished by ...... 13 

• -, experiments on iron furnished by , . . . .150 

Rivets, effects of, on the strength of boilers, .... 234 

Rivet-holes, unequal strains on ..... . 236 

Rumford’s results on latent heat, ...... 43 

Russian iron, experiments on . . . . . , 180 


Salisbury Iron Company, materials furnished by 

---, experiments on iron made by 

Scale, diagonal, for gauging iron, 

Sections, original, of bars .... 

- 1 - and filed compared, . 

Sheet iron cylinders for specific heats, 

Shield for the standard piece in transitu, 

Schoenberger &. Son, materials furnished by 

-, experiments on iron made by 

Shorb, Barnet, experiments on iron manufactured by 

-, materials furnished by 

Southern’s result on latent heat. 

Spang, Henry S. &. Son, materials furnished by 

-, experiments on iron manufactured by 

Specific gravity of boiler-iron, . 

-heat by vaporization, 

-heat of iron, .... 

-heat of iron, tables of 

-gravity, little influence on, by annealing iron, 

— heat of iron, general table of . 


13 

192 
16 
13 
229 
35 
21 
13 

108, 109. 112—115 
. 94,95 

13 


Specimens, preparation of 
Standard of high temperatures, 

-piece of pyrometer 

-tenacity of copper, 

Strength in different directions of the rolled sheet, 

-, least, of materials for steam-boiler, 

-of boiler-iron made by different processes, 

-of copper, tables of 

-of iron from different sorts of pig metal, . 

-of rolled copper, 

Structure of iron not unilorm, 

Swedish iron, experiments on 

Telford’s experiments on tenacity, 

Temperature, elevated effects of, on copper, 

-, table of effects of, on copper, 


-, remarks on 


Tenacity affected by annealing, 

-, no, where supposed to be situated, 

-, standard of . 

Tennessee iron, experiments on 


in water vessel, 


Thermometers, sluggishness of . 

Thomas, Valentine & Co., iron furnished by 
Thompson, J., experiments on iron furnished by 
Thompson, T., on latent heat, 




• 

43 

• 

• 


. 13 



• 

48—93 

• 

• 


. 232 



• 

46 

• 

• 


. 20 



24—35. 40 

• 



246 

• 

• 


. 39 



• 

13 

• 

• 


16 



« 

19 

• 

• 


. 74 



• 

228 

• 

• 


. 57 



• 

147 

• 

• 


58—73 



• 

189 

• 

• 


. 57 



• 

14 

* 

• 


182. 185 

• 

• 


4. 247 

• 


• 

47 

• 

• 


. 210 

• 



212 

• 

• 


. 240 

• 



74 

• 

• 


. 74 

• 



170—179 

osure to hot metals, 67 

• 


• 

22 

• 

• 


. 48 

• 


• 

13 

• 

• 


. 150 

• 


• 

43 

































254 


V 


Tin, melted, used in trials of specific heats, .... Page 40 

-and Lead, bath of, how used, ...... 139 

Topics, distinct, embraced in this investigation, . . . .5 

Tyler, R., experiments on iron furnished by . . 150 

Unequal extensibility of laminae in plate-iron, . . . . .93 

Uniformity, degree of, in filed bars of iron . .... 79 

Ure on latent heat, ........ 43 

Valentine & Thomas, materials furnished by .... 13 

Valentine, G., experiments on iron furnished by .... 150 

Vaporization, specific heat, determined by ... 46 

Vapour, latent heal of . . . . . . . .42 

Verification of pyrometer, ....... 20 

Watt on latent heat, ........ 43 

Wire, Phillips’ experiments on ... . 158.244 

-, strength of, before and after annealing, ..... 244 

Wood, Nicholas, on the friction of iron, ..... 10 

Yeatman 5c Woods, experiments on iron made by . . . 170—179 

























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